Koyanagi Technique Research Articles

Uroflowmetry As a Long-Term Urological Outcome Assessment of Proximal Hypospadias Cases Repaired by Mansoura Modification of The Koyanagi Technique

Uroflowmetry As a Long-Term Urological Outcome Assessment of Proximal Hypospadias Cases Repaired by Mansoura Modification of The Koyanagi Technique

Koyanagi urethroplasty for proximal hypospadias: A stage procedure?

To report experience and technical refinements with the Koyanagi urethroplasty for proximal hypospadias. A retrospective study was conducted between 2004 and 2017. Medical records of patients treated by the Koyanagi technique were investigated. The penile ventral skin was closed either with a Byars flap or using an "Ombredanne's chasuble" (OC). The cohort was divided chronologically into two groups of the same number of patients (early -E- and late experience group-LEG-). Demographics, anatomical findings and surgical outcomes were compared between groups using univariate analysis. A logistic regression was performed to assess factors associated with the occurrence of a postoperative urethrocutaneous fistula or urethroplasty dehiscence (UD). The Koyanagi urethroplasty was performed in 67 patients, 33 in the EEG and 34 in the LEG. The overall surgical complication rate was 64.2% (n=43), including 42 fistula or UD, higher in the EEG (81.8%) than in the LEG (44.1%, P<0.01). However, in the LEG, patients underwent the surgery older and the use of OC more frequent. After multivariate analyses, factors associated with a postoperative fistula or UD were the year of surgery (OR=0.71 [0.53-0.96] P=0.02), the age at surgery (OR=1.11 [1.01-1.22], P=0.03); contrary to the skin coverage method or the stenting duration (P>0.05). An urethral stenosis occurred in 1 patient (1.5%). At last follow-up, 64.2% of patients required a further procedure and 80.6% of urethral meatus were glandular. In this study the complication rate, particularly the urethrocutaneous fistula, remained high. Urethral stenosis, were rare but the follow-up was too short to clearly identified them. Considering as a 2 stage procedure koyanagi uretroplasty allows to obtain finally good results. III.

Neomodified Koyanagi technique for severe hypospadias with one-stage sealed Y-shaped penis foreskin vascular protection surgery.

Proximal hypospadias defects represent the most challenging aspect of maintaining blood supply to the flap, which eventually leads to a high rate of complications. We modified a sealed Y‐shaped penis foreskin vascular protection technique, which can repair the urethra in a single stage. The inner plate of the foreskin was cut along the coronal sulcus, and both sides of the urethral plate were cut as deep as Buck's fascia. The "Y"‐shaped foreskin flaps on both sides of the mouth that are continuous with the urethral plate were sutured to form a new urethral skin tube. The urethral skin tube was turned to the ventral side, and the foreskin was reshaped and sutured. A total of 89 children had their urinary catheters removed 4 weeks after the operation. All children were evaluated at least once a year for 3 consecutive years. There were 11 patients with urine leakage that occurred after the operation. These children, diagnosed with urine leakage, underwent successful repair after the leakage occurred. There were no urethral strictures after the operation. The one‐time success rate of this operation was 87.6% (78/89), and the incidence of urethral fistula was 12.6% (11/89). The results showed that sealed Y‐shaped penis foreskin vascular protection surgery was safer and had a higher operation rate than the traditional hypospadias repair technique. Modifying Koyanagi repair by our improved Koyanagi hypospadias repair is an excellent technique with relatively low complication rates.

Results of the one-stage proximal hypospadias repair with modified Koyanagi technique: A prospective cohort study in a single Vietnam centre

IntroductionProximal hypospadias is the most severe type of hypospadias. Our approach to Koyanagi technique for proximal hypospadias aims to improve the blood supply to the neourethral flaps and reduce meatal complications. MethodsOur prospective study included 75 patients who were operated for proximal hypospadias by our Koyanagi technique at Viet Duc hospital between January 2019 and December 2020. The clinical information obtained included a detailed medical history; preoperative, intraoperative, and postoperative data; short-term outcomes by the HOSE score were evaluated by a different physician. ResultsThe mean (range) age was 3.59 ± 2.41 years (1.5–14), 86.7% under 5 years old. There are 31 penoscrotal, 31 scrotal, and 13 perineal hypospadias. The length of the neourethra ranged from 3.5 to 8 cm, mean 5.02 ± 0.88 cm. Evaluation of the surgeon at 6 months after surgery: primary success 81.3%. Complications occurred in 14 cases (18.7%), included 10 urethrocutaneous fistula and 4 dehiscence of the urethra. No cases of meatal stenosis or recession, urethral stricture, urethral diverticula. The mean HOSE score was found to be 14.47 ± 1.35, ranged 11 to 16. 57 patients (76%) had a total HOSE 14 and above and 18 patients had score below 14 (24%) ConclusionOur modified Koyanagi technique give us a good result for one-stage reconstruction of proximal hypospadias. Applying the HOSE score makes postoperative evaluation of hypospadias more objective and reliable.

Meta Analysis Study of Complications Following Repair of Mid Penile Hypospadius using Different Surgical Techniques

Abstract Background Hypospadias is one of the most common congenital defects affecting the external male genitalia. The incidence is 1 in 250 male newborns, although its incidence seems to be increasing. Hypospadias is defined as an insufficient development of the urethral fold and the ventral foreskin, with or without penile curvature. The urethral opening is located more proximally anywhere between the tip of the penis and the perineum. Aim of the Work The aim of this study is to determine the best surgical technique with the least complications for repair of mid-penile hypospadias. Materials and Methods This systematic review and meta-analysis was performed in accordance to the recommendations of the Meta-analysis of Observational Studies in Epidemiology (MOOSE) statement. MOOSE is a reporting checklist for Authors, Editors, and Reviewers of Meta-analysis of interventional and observational studies. According to International committee of medical journal association (ICJME), reviewers must report their findings according to each of the items listed in those checklists. Results Fistula is less common after Preputial island flap technique. Fistula is more common with Modified koyanagi technique. Meatal stenosis is less common after Mathieu and Preputial island flap techniques. Meatal stenosis is more common after TIP technique. Wound Dehiscence is not common after lateral based flap and modified koyanagi and Onlay island flap techniques. Neourethral Stricture is not common after lateral based flap and Mathieu and Onlay island flap techniques. Conclusion The Mathieu and Preputial island flap techniques for mid-penile hypospadias reconstruction are associated with a significantly lower risk for postoperative urethral stricture and may be the preferred method for hypospadias. However, the clinical implications of the results can be discussed because the risk of stricture in all procedures was low. The implications for research are obvious because there had been no studies that provided firm guidelines on the best method for the operative intervention for hypospadias. Further trials are still needed to confirm our findings.

New Modification of Koyanagi Technique Using Dartos Muscle Flap in Management of Proximal Hypospadias

Background: One stage urethroplasty through parameatal foreskin flap (OUPF) available for all types of hypospadias was first described by Tomohiko Koyanagi (1983). High complication rates were reported. Objective: To evaluate the outcome of Koyanagi technique modification using dartos muscle as a 2nd layer because it has a high vascularity, very thin, easily elevated, and leaves no complications. Patient and methods: This study was conducted in the Plastic Surgery Department at Menoufia University, during the period of April 2017 to April 2019. Thirty cases for proximal hypospadias were included during this study. After chordee release, urethra was constructed using Koyanagi technique and adding scrotal dartos muscle flap as a 2nd layer. Results: Patient's age ranged from 1 to 4 years with mean age of 2.83 ± 1.17. All of the 30 cases were with proximal hypospadias and had severe chordee. Early complications were detected as bleeding in 2 patients (6.6%). One patient (3.3%) reported for retention due to obstruction of the inserted catheter. Another case (3.3%) showed wound infection. The reported late complications were fistula in 6 patients (20%), meatal recession in 5 patients (16.6%), meatal stenosis in 3 patients (10%), and diverticulum in one patient (3.3%). Conclusion: The modified Koyanagi one stage repair of proximal hypospadias is an innovative technique and realize many criteria for expected effective operating results. The use of dartos muscle flap as a cover for the urethroplasty improves the results and minimize complications.

The modified Koyanagi technique versus two-staged urethroplasty using buccal mucosal graft in managing proximal hypospadias: a randomized clinical trial

Background One of the most challenging cases in correction is proximal hypospadias. There are many techniques used, but no technique has shown success or acceptance universally. The purpose of our study is to compare the modified Koyanagi (MK) technique and two-staged urethroplasty by buccal mucosal graft techniques in managing proximal hypospadias types regarding rate of success, postoperative complications, and cosmesis. Patients and methods A total of 40 patients with proximal hypospadias types were enrolled, and these patients underwent surgical repair using MK technique or two-stage urethroplasty using buccal mucosal graft techniques. Patients were randomized into two equal groups (n=20): group A underwent MK technique, and group B underwent two-staged urethroplasty using buccal mucosal graft techniques. The follow-up ranged from 6 to 18 months. Results The rate of success was 60% in group A compared with 75% in group B. Higher incidence of fistula was in group A (six cases) than group B (two cases), urethral stricture was the same (two cases in each group), meatal stenosis was less in group A (two cases) than group B (eight cases), and residual chordee was more in group A (two) than B (one), with no penile rotation in both groups. Conclusions The MK for repair of proximal hypospadias is a good technique and gives successful surgical results but requires meticulous technique and tedious preservation of blood supply. Two-staged urethroplasty is a technically straightforward and feasible technique, with less fistula rate, but requires more time, as a two-session operation, with good results in severe chordee and success rate.

Two simple modifications can potentially change the future of proximal hypospadias surgery. Our series and a review of the literature.

Background/ObjectiveTo draw a hint towards two simple modifications that could potentially decrease the complication rate.Patients and MethodsIt was a single center, single operator and retrospective study. All patients with severe hypospadias operated according to koyanagi with or without modifications were presented. The surgical technique was described. Complications like fistula, stenosis, dehiscence and urethral diverticulum were studied.Results and LimitationsNineteen patients were included and presented in a chronological manner. The first four patients were operated according to the original koyanagi technique. The next 15 patients were operated according to koyanagi and the urethroplasty was covered by a tunica vaginalis flap. In 10 of them, glanduloplasty was done primarily and in the last 5 patients, glanduloplasty was done as a secondary procedure. The complication rates were 100% in the original koyanagi group, and 0% in the subset were glanduoplasty was deferred.ConclusionsSystematically covering the urethroplasty with a tunica vaginalis flap and deferring the glanuloplasty might ameliorate the results of the koyanagi technique.

Intérêt de la technique de Koyanagi dans le traitement de l’hypospadias posterieur chez l’enfant

IntroductionThe koyanagi technique because of its satisfying results and less risk of postoperative complications for the patient has generated an increasing interest during recent years. ObjectiveTo report the indications and the results of the koyanagi technique. Patients an methodsThis is a descriptive retrospective study of patients admitted in the pediatric surgery's department of the EPS Monastir, Tunisia for proximal hypospadias and operated on according to Koyanagi's technique during the period from 02 january 2006 to 30 june 2013, with subsequent follow-up of at least 02 years. ResultsThe data of total 35 patients were collected. The average age at the first consultation in pediatric surgery was 12.2 months and the age at surgery was 28.8 months with extremes ranging from 12-55 months. The mean operative time was 166.1 min. The average stay at hospital was 7.9 days. Only 4 patients (11.4%) presented immediate complications. Reoperation was indicated for 23 cases and indications were by decreasing order of frequency: dehiscence (34.3%), fistula (11.4%) and dehiscence with persistent penile-scrotal transposition (2.9%). The final clinical evaluation of the surgery found that meatus was distal in the majority of cases (85.7%), two patients kept a residual curvature estimated as being minimal and not requiring any further surgery and none of our patients presented abnormalities of the urinary stream. ConclusionsKoyanagi's technique in repairaing proximal hypospadias seems to be an excellent option especially in cases of severe curvature but with a high rate of complications.

Onlay urethroplasty with unilatreral parameatal penopreputial flap

Background/purpose: One-stage urethroplasty with bilateral parameatal foreskin flap was first described by Tomohiko Koyanagi for cases of severe hypospadias. He also introduced the onlay urethroplasty with unilateral parameatal foreskin flap for distal hypospadias. Emir and colleagues in 2000 devised a modification of the bilateral Koyanagi repair of severe hypospadias. We in turn modified the (unilateral) Koyanagi technique for the repair of hypospadias without chordee. The aim of this study is to analyze the results of the Mansoura modification of the (unilateral) Koyanagi technique as a one-stage repair of hypospadias without chordee. Patients and methods: During the period from March 2013 to March 2015, 30 patients underwent treatment of hypospadias without chordee using the modified onlay urethroplasty with unilatreral parameatal penopreputial flap (modified unilateral Koyanagi technique). Results: The patients’ age at the time of surgery ranged from 6 to 30 months. Sixteen cases had distal penile meatus, 10 had mid-penile meatus; and four had proximal penile meatus. The follow-up ranged from 3 months to 1 year. Primary success occurred in 28 (93%) cases with accepted cosmetic appearance. Complications occurred in two (7%) cases, in the form of urethrocutaneous fistula. There was no incidence of meatal stenosis nor recession, urethral stricture or flap necrosis. Conclusion: The Mansoura modification of the onlay urethroplasty with unilatreral parameatal penopreputial flap (unilateral Koyanagi) is applicable for all forms of hypospadias without chordee showing acceptable results. Keywords: hypospadias, modified Koyanagi, one-stage urethroplasty, onlay urethroplasty with parameatal penopreputial flap, original Koyanagi

Modification of the Koyanagi Technique for the Single-Stage Repair of Proximal Hypospadias.

We describe a modification of the Koyanagi technique for hypospadias in an attempt to reduce complications and improve results. Between January 2005 and July 2012, 21 patients underwent treatment of proximal hypospadias using a modified hypospadias repair. The procedure involved making a U-incision similar to that in a Thiersch-Duplay repair to preserve the blood supply to the tubular neourethra. The neourethra was reconstructed by island penile skin. An M-incision was made in the glans, and the meatus was attached to tip of glans. Flaps were harvested from both sides of the penis preventing postoperative penile turn. Cosmetic and functional, long-term (mean, 12 months) recovery was excellent. Complications consisted of 3 cases of urethrocutaneous fistula (14.2%), which were corrected surgically, and 2 cases of penile skin necrosis. There were no instances of meatal stenosis, diverticulum, or urethral stricture. Bifid scrotum was present in 6 patients, and associated penoscrotal transposition was present in 15 patients. Both of these associated defects were corrected at the time of surgery. The modified technique permits 1-stage repair of proximal hypospadias with a low complication rate, the satisfactory recovery.

A New Modification of the Koyanagi Technique for the One-stage Repair of Severe Hypospadias

To describe a new modification of the Koyanagi technique for the one-stage repair of severe hypospadias and its short-term outcomes. Our modified Koyanagi technique was performed in 24 patients with severe hypospadias between February 2012 and January 2015. The age of the patients ranged from 1.9 to 11.9 years (mean = 3.5 years). The flap design was similar to the Koyanagi technique, but our modified technique highlighted the following points: after the chordee was completely corrected, the urethral plate was recreated using foreskin, and then a U-shaped incision was made on the original and recreated urethral plate (as in the Duplay technique); a pedicled flap of the tunica vaginalis or scrotal dartos was used for additional coverage of the neourethra. The operation time lasted from 120 to 150 minutes (mean = 140 minutes). There were 5 patients (20.8%) who developed complications: 4 patients (16.7%) developed a fistula and 1 patient (4.2%) developed dehiscence of the urethra. There were no reported urethral strictures, meatal stenosis, or urethral diverticula. The complications in the 5 patients were successfully addressed with secondary repair, and all patients achieved satisfactory cosmetic and urethral functional results. The modified Koyanagi technique simplified the operation and better preserved the blood supply to the flap. The additional coverage of the neourethra using a pedicled flap of the tunica vaginalis or scrotal dartos significantly decreased the rate of fistula formation. This technique is highly suitable for the one-stage repair of severe hypospadias with penoscrotal transposition.

Application of modified koyanagi technique with coverage by tunica vaginalis of testis in severe hypospadias

To investigate the clinical effect of modified Koyanagi technique with coverage by tunica vaginalis of testis in severe hypospadias. 49 cases with severe hypospadias treated from Jan. 2009 to Sep. 2011 were retrospectively studied. 25 patients underwent Koyanagi technique with coverage by tunica vaginalis of testis. 24 cases underwent one-stage Duplay + Duckett technique in the same term. The patients were followed up for 7-24 months. Among the 25 children treated with Koyanagi procedure, 20 cases were cured, 5 patients had postoperative complications, including urethral fistula in 3 cases,urethral stenosis in 2 cases. At the same time, in the Duplay + Duckett group, 17 cases were cured, 7 children had postoperative complications, including urethral fistula in 4 cases, and urethral stenosis in 3 cases. All the patients with urethral fistula were repaired successfully 6 months after the first surgery; The urethral stenosis were cured by dilatation within 1 to 3 months. The successful rate in the 2 groups had no significant difference(P >0.05). Koyanagi technique with coverage by tunica vaginalis of testis is relatively simple with similar effect as Duplay + Duckett technique for severe hypospadias.

Choosing a technique for severe hypospadias

We participate in humanitarian missions in Madagascar during which we treat severe hypospadias. We report our experience and results with these patients, in these conditions, and discuss our choice of technique in this particular setting. We retrospectively reviewed the data of 27 patients operated for severe hypospadias during our humanitarian missions in Madagascar between November 2006 and September 2009. Twenty one patients underwent a modified Koyanagi procedure, three underwent a Duckett urethroplasty, two an onlay island flap, one an augmented Duckett and one a tubularised plate urethroplasty. Two patients who underwent a modified Koyanagi repair also had a Nesbitt dorsal plication. Patient age at the time of surgery ranged from 22 to 198 months with a median age of 54.1 months. Mean follow-up was 16 months. Of the 21 patients who underwent a modified Koyanagi procedure, 16 presented at least one complication (76%): A fistula developed in 12 patients (57%), meatal regression developed in 7 (33%) and 2 showed complete wound dehiscence (9.5%). None developed stenosis or urethrocoele. In this particular setting, the postoperative complication rate is high. Nevertheless, the Koyanagi technique is appropriate, because its complications are easy to treat and there is always sufficient ventral tissue for the secondary operation, if necessary.

Modified Koyanagi's procedure for proximal hypospadias: Our experience

Koyanagi described an elegant technique for one-stage proximal hypospadias repair. It is particularly suited for the most severe forms of hypospadias. A modified Koyanagi technique was used to repair the hypospadias in 14 children, aged 3-9 years. One child developed breakdown of the suture line, three other children developed small urethrocutaneous fistula needing closure and one child had post-operative meatal stenosis. Despite the high rate of complications, modified Koyanagi's procedure is a good procedure of choice for severe/proximal hypospadias.

Modified Koyanagi Technique in Management of Proximal Hypospadias

Background/Purpose: One stage urethroplasty with parameatal foreskin flap (OUPF) applicable to all types of hypospadias was first described by Tomohiko Koyanagi, however high complication rates were reported .The aim of this study is to analyze the results of a modification of the Koyanagi technique as a one-stage repair of proximal hypospadias. Patients and Methods: During the period of from March 2008 to March 2009, 30 patients underwent treatment of proximal hypospadias using the modified Koyanagi technique. Patient age at the time of surgery ranged from 6 to 24 months. In all cases, the urethral opening was at or just proximal to the penoscrotal junction. Follow up ranged from 3 months to 1 year. Results: Primary success occurred in 27 cases (90%) with accepted cosmetic appearance. Complications occurred in 3 cases (10%). Urethrocutaneous fistula occurred in 2 cases (6.7%). Meatal recession occurred in 1 case (3.3%). There was no incidence of meatal stenosis, urethral stricture, residual chordee or complete flap necrosis.

Original Koyanagi urethroplasty versus modified Hayashi technique: Outcome in 57 patients

To compare outcomes of the original Koyanagi technique with the Hayashi modification in severe hypospadias, i.e. hypospadias with a division of the corpus spongiosum located behind the penile midshaft associated with marked hypoplasia of the ventral aspect of the penis and a non-preservable urethral plate. Choice of technique for treating severe hypospadias is discussed. Twenty-six patients (group I) were operated in Lyon using the original Koyanagi procedure and 31 (group II) underwent a modified Hayashi procedure in Paris. Most patients received preoperative androgenic stimulation. Mean follow up was 25 months (group I) and 34 months (group II). Sixteen patients (61.5%) in group I and 19 (61.3%) in group II developed complications leading to 21 additional procedures in each group. Urethral dehiscence was found in 11/26 patients in group I (42.3%), and in 6/31 patients in group II (19.3%); fistulae were respectively found in 5/26 (19.2%) and 12/31 (38.7%), and stenosis in 9/26 (34.6%) and 5/31 (16.1%) patients. Urethrocele was found in 7/26 (26.9%) and 5/31 (16%) patients, respectively. Twelve (group I) and 7 (group II) patients are awaiting re-operation. Although the complication rate is quite similar between the original and the modified Koyanagi procedure, the Hayashi technique seems to provide a better distal blood supply to the reconstructed urethra.

Neo-modified Koyanagi technique for the single-stage repair of proximal hypospadias

Purpose To retrospectively analyze the results of a modification of the Koyanagi hypospadias repair developed to reduce complications. Materials and methods Twelve boys underwent a modified Koyanagi repair over the past 3 years. The technique included the preservation of a wide vascular pedicle for each parameatal flap. The distal urethral plate was left intact and attached on each lateral side to the medial side of each distal Koyanagi pedicle flap. Results One boy (8%) developed a urethral fistula. There was no instance of meatal stenosis, sacculation or urethral stricture. Conclusions Modifying the Koyanagi repair by preserving a wide vascular pedicle for the distal skin flaps and utilizing the distal urethral plate as the base for the distal neourethra has lowered the incidence of complications. This technique is a suitable alternative to a two-stage approach for the correction of proximal hypospadias.

Results of Single Staged Hypospadias Surgery to Repair Penoscrotal Hypospadias With Bifid Scrotum or Penoscrotal Transposition

During the last 10 years there has been controversy in the approach to severe hypospadias. Many pediatric urologists have elected to perform a 2-staged procedure to minimize complication rates and improve cosmesis. We continued to perform a single staged repair using the Hodgson XX or Koyanagi technique for even the most severe hypospadias. We review our results during the last 5 years in severe cases of penoscrotal hypospadias with bifid scrotum or penoscrotal transposition. The medical records of 20 consecutive children presenting to a single surgeon from 1996 to 2000 with severe penoscrotal hypospadias were reviewed. Patients underwent a 1-stage repair using an operative microscope. Cases not requiring further surgery were grouped as successful while cases requiring subsequent procedures were considered as complications. After an average followup of 23 months 16 patients have not required subsequent procedures. Two patients had urethrocutaneous fistulas and 2 had a urethral diverticulum for an overall complication rate of 20%. All 4 patients were successfully treated with 1 additional procedure and have not required further intervention. Another patient with a small urethral diverticulum is being treated conservatively. All patients had satisfactory cosmetic results. We believe that a single staged repair can be safely and effectively performed even in patients with the most severe penoscrotal hypospadias. The Hodgson XX and Koyanagi repairs are excellent techniques with relatively low complication rates. Pediatric urologists should continue to use these techniques in their armamentarium and strive to perfect a 1-stage approach to severe hypospadias.

SEVERE HYPOSPADIAS REPAIR WITH MEATAL BASED PARACORONAL SKIN FLAP: THE MODIFIED KOYANAGI REPAIR

Various techniques have been reported to repair severe hypospadias. The Koyanagi repair uses a meatal based foreskin flap. We modified this procedure and reviewed the outcome of the repair of severe hypospadias. The modified Koyanagi repair was performed in 151 children 7 months to 15 years old (mean age 3 years) with severe hypospadias. The records of these patients were reviewed. In all cases the meatus was at or proximal to the penoscrotal junction. Followup was 6 months to 16 years (mean 6 years). Flap design is the same as in the Koyanagi repair, although our modified technique requires removal of the subcutaneous tissue of the distal portion of the flap, which acts as a full-thickness free skin graft. A fistula developed in 19 patients (12.6%), meatal stenosis in 3 (2%) required meatoplasty and infection in 2 (1.3%) resulted in a regressed meatal position. Good cosmetic results were achieved in all except the latter 2 cases. Our modified Koyanagi repair affords an excellent cosmetic appearance. The complication rate is relatively low and compares favorably with that of other techniques.