Two Stage Meshgraft Urethroplasty

F. Schreiter

25.1 Introduction - 206

25.2 Basic Considerations in Complex Urethral Strictures - 206

25.3 Pathophysiology - 206

25.4 Preparing for Surgery - 206

25.4.1 Position - 207

25.4.2 Instruments - 207

25.5 Surgical Technique - 207

25.5.1 Posterior Urethroplasty - 207

25.5.1.2 Second Stage - 209

25.5.2 Posterior Urethroplasty with Partial Replacement of the Urethra - 211

25.5.3 Complex Strictures Along the Entire Length of the Urethra -212

25.6 Tricks and Pitfalls in Mesh-Graft Urethroplasty - 214

25.6.1 Dressing Technique - 214

25.6.2 Postoperative Care - 215

References - 215

25.1 Introduction

Most uncomplicated strictures of the anterior and posterior urethra are successfully treated with a one-stage procedure. Among these procedures are stricture resection and consecutive end-to-end anastomosis or contemporary methods of tissue transfer such as flap procedures. However, complex strictures with significant scar tissue formation of the urethra, strictures that have undergone prior repeated surgery, and urethra malformations found in severe hypospadia cases continue to present a challenge for surgery. The problems arise from a lack of the healthy elastic tissue needed to reconstruct the urethra. This applies in particular for long strictures that involve the entire length of the urethra.

The classical two-stage methods developed in the 1950s, represented here by the Bengt-Johanson procedure, were based on marsupilization of the restricted urethra, followed by a second operative stage after the first stage had healed. All these methods used scrotal or peri-neal skin for reconstructing the urethra. Bengt-Johanson's great achievement was the development of a reconstructive-surgery urethral treatment that is suitable for all types of strictures. However, the drawback of this method was that hair growth occurred because scrotal and perineal skin was used, which could lead to chronic urinary tract infection, abscesses, calculi, and fistulas. Scrotal skin, which is extremely elastic, often resulted in the formation of diverticula and sacculations in the neourethra.

Consequently, the author investigated the use of the mesh-graft procedure in an attempt to become independent of scrotal or perineal skin by using hairless skin, which is transplanted free in a two-stage procedure. The high contraction and stricture recurrence rate, when penile hairless skin was used in a single stage procedure, precluded us from using our technique as a single-stage procedure.

Although the two-stage mesh-graft procedure as a safe operation can be used for every type of stricture, its real advantage is apparent when used for complex strictures, especially when there is severe scar tissue formation and absence of healthy penile skin for reconstruction of the neourethra.

25.2 Basic Considerations in Complex Urethral Strictures

The surgical principle is the free transfer of full-thickness skin (inner layer of the foreskin or distal penile skin), or very thin split-skin grafts in circumcised patients. A mesh-graft dermatome is used to process the loose grafts into a mesh. This mesh-graft is transplanted to the location of the exposed and marsupialized urethra. After the complete epithelialization of the free transplanted mesh-

graft, there will be an ample amount of hairless, vital, and soft tissue that can be used to reconstruct the new urethra in a second surgical stage.

To improve surgical results, three important principles should be taken into account when performing surgery on complex urethral strictures:

1. The tissue required to easily shape a new urethra that is wide enough and free from tension can be created through loose transplants of full-thickness skin (the inner layer of the foreskin has proven best for this purpose) or distal penile shaft skin, or - in most cases of long and complicated strictures - split-skin grafts.

2. This results in a neourethra that is free from hair, thereby preventing chronic infection, calculus formation, restricturing, and sacculation.

3. Free grafts should heal in an open and dry environment. This requires a two-stage surgical procedure. Therefore, for reasons of dependability and security, very complex strictures should be treated with a two-stage surgical procedure.

Two-stage mesh-graft urethroplasty meets these requirements for treating complex urethral strictures.

25.3 Pathophysiology

Extended and complex urethral strictures are either iatrogenic, the result of a traumatic insertion of endoscopic instruments (catheter, cystoscope, resectoscope) or the result of a urethritis caused by prolonged indwelling catheter use. This especially occurs with long-term indwelling catheter treatment in patients with cardiac or post-traumatic shock, through pressure necrosis and hypotension. Secretion of mucous and infection along the catheter in conjunction with pressure damage caused by the foreign body (catheter) promote the formation of periurethral infiltrates. The infection then leads to the formation of scarred bridges between opposite regions of mucous membranes, and above all to a cicatricial contraction of the corpus spongiosum urethrae (spongiofibrosis). Postoperative infections, calculus formation, and recurrence caused by repeated operations on a urethral stricture, especially when scrotal skin was used to reconstruct the urethra, results in an extended and complex stricture, often affecting the meatus of the urethra. The more pronounced the scarring, the greater the urethra's tendency to shrink and the more extensively the urethral stricture will manifest.

25.4 Preparing for Surgery

The patient's genital area is shaved, including the perineal region. The bowels are thoroughly emptied prior to surgery using laxatives.

Position

In frontal urethral stricture cases, patients can be positioned in a supine position. The lithotomy position is used in cases of posterior or extended strictures.

Instruments

25.5

Surgical Technique the hairline, and buttocks is an obvious choice due to the lithotomy position of the patient undergoing urethral surgery.

To remove the split skin, use an electric or compressed-air-driven split-skin dermatome with adjustable incision width and size (O Fig. 25.3A, B).

Compressed air or an electrically driven split-skin dermatome for harvesting the split thickness skin graft and a mesh-graft dermatome to prepare the mesh (e.g., E. Zimmer with 1x1.5 matrix), one or two 1-1.5 ratio mesher sheets, a set of Benique sounds, knob sounds, bipolar pick-ups for electrocoagulation, and Metzenbaum scissors are required for surgery.

25.5.1 Posterior Urethroplasty 25.5.1.1 First Stage

In uncircumcised patients, the foreskin is used, as this tissue is best suited for full-thickness skin grafts. First, perform an extended circumcision (O Fig. 25.1). Stretch the 50-60 cm2 of foreskin obtained in this way onto the cork board, carefully and completely remove the subcutaneous tissue using the scissors. The fatty tissue has been completely removed when no larger vessels are visible on the full-thickness skin graft. This is necessary to achieve rapid revascularization of the free graft from the nutritive base (O Fig. 25.2).

If no foreskin is available, thin split-skin grafts may be used. Here, skin from the inside thigh, the groin above

Mesh Graft
□ Fig. 25.2. Defatting of the graft
Foreskin MacaroniMesh Graft

O Fig. 25.1. Circumcision

O Fig. 25.3. Harvesting of the mesh-graft (split-skin dermatoma)

O Fig. 25.1. Circumcision

O Fig. 25.3. Harvesting of the mesh-graft (split-skin dermatoma)

Using a mesh-graft dermatome, the foreskin or shaft skin is processed to a mesh, in a 1:1.5 ratio (□ Fig. 25.4).

The skin on the penile shaft is incised in the raphe along the length of the stricture (□ Fig. 25.5).

The stricture is cut open along its length with a pair of scissors (□ Fig. 25.6).

The stricture must be laid open down to the healthy urethral tissue, where no spongiofibrosis is evident along the spongy body of the urethra (□ Fig. 25.7).

The free meshed graft is sewn into the edge of the marsupialized urethra and the edge of the penile skin. As there is a certain shrinkage tendency during the healing

Millimeter PenisStaged Urethroplasty

O Fig. 25.5. Skin incision in anterior strictures

O Fig. 25.5. Skin incision in anterior strictures

□ Fig. 25.7. Stricture opened process, the sewn-in grafts should be as wide as possible. The graft is fixed in place by means of a interrupted, running, absorbable suture (□ Fig. 25.8).

After 1-2 weeks, the graft has healed and the epithe-lization is complete.

After 8-12 weeks, the graft has stabilized to such an extent that the 2nd stage of the surgery, shaping the new urethra, can be carried out

25.5.1.2 Second Stage

The second stage is performed after complete epitheliali-zation of the graft. The reconstruction of the neourethra should be not performed before 8 weeks. The longer the time between the first and the second step of the operation, the better the quality of the tissue that is used for the reconstruction of the urethra.

A sufficiently wide circumferential incision of the graft is made (□ Fig. 25.9).

The mobilization of the transplanted penile skin has to be directed laterally, not mobilizing the transplant tissue, which is used for the reconstruction of the neou-rethra.

A 24-Fr catheter is used to close the graft, which is elastic, supple, has good circulation, and tends to roll up, with an interrupted running suture using absorbable monofilament thread. Pick a suture technique whereby an inverting, interrupted stitch occurs at the outside of the

Mesh Graft
□ Fig. 25.8. Mesh-graft transplant, sutured

cut edge of the graft, resulting in suture without leaving epithelium insulae outside, which prevent later fistulas (□ Fig. 25.10).

Staged Urethroplasty
Elastic Penis Meatus
□ Fig. 25.10. Peritomy of the healed transplant

To cover the skin defect, the penile shaft skin must now be completely mobilized. Use the scissors to remove the epithelium from the edges of the glans; this will form the posterior wall of the meatus to be created (O Fig. 25.11 ).

To begin forming an asymmetrical advancement flap according to Marberger and Byars, the outer penile skin has to be incised dorsally (O Fig. 25.12).

Neourethra
O Fig. 25.11. Reconstruction of the neourethra(see suture technique)

On the dorsal side of the penis, connect the skin of the penile shaft to the edge of the inner foreskin layer on the glans with single stitches (□ Fig. 25.13).

The top of the flap of penile shaft skin, which has been rotated to the front, is sewn to the edges of the glans, from which all epithelium has been removed, to form the anterior wall of the passage to be formed. This puts the meatus nearly at the tip of the glans.

The asymmetrical rotation flap is put on the penile shaft in such a way that the suture line of the newly formed neourethra is covered (□ Fig. 25.14).

Staged Urethroplasty
□ Fig. 25.13. Dorsal incision and creating the Byars flap
Byars Flap

O Fig. 25.12. Mobilizing the penile skin

O Fig. 25.14. Suture of the skin to the coronal rim

O Fig. 25.12. Mobilizing the penile skin

O Fig. 25.14. Suture of the skin to the coronal rim

The Marberger/Byars sliding-flap technique completes the stricture repair (□ Fig. 25.15).

A loose circular pressure bandage ensures good hemos-tasis. Thin suction drainages may be used for draining.

25.5.2 Posterior Urethroplasty with Partial Replacement of the Urethra

The bulbar section of the urethra is nearly always easily accessed via a midline perineal incision. Other access paths to the rear of the urethra, involving the formation of a broad-base perineal flap, are usually unnecessary and are only required if there is extreme scarring in the perineal raphe.

The completely obliterated urethra is laid open and resected, exposing the proximal and distal healthy urethra (O Fig. 25.16).

The resultant urethral defect is lined with a mesh-graft and fixed at the edge of the perineal skin and at the rim of the urethral stumps with monofilament suture 5-0 (O Fig. 25.17).

After healing of the transplant, the reconstruction of the urethra is made analogously to the anterior urethro-plasty.

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Responses

  • saimi laukkanen
    How to strch panis cork skin?
    11 months ago
  • orlando burrows
    How to prepare a patient for second stage urethroplasty?
    5 months ago

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