Reconstruction of the Fossa Navicularis 17

Reconstruction of the Fossa Navicularis

G.H. Jordan, K.F. Rourke

17.1 Reconstruction of Acquired Meatal Stenosis and Strictures of the Fossa Navicularis – 138

17.2 Reconstruction of Childhood Meatal Stenosis – 138

17.2.1 Isolated Stricture of the Fossa Navicularis Following Transurethral Resection of the Prostate – 139

17.2.1.1 Y-V flap Procedures – 139

17.2.2.2 Resurfacing of Fossa Navicularis – 139 17.2.2.3 Transverse Ventral Penile Skin Island – 139

17.2.3 Stricture Associated with Early Balanitis Xerotica Obliterans – 142 17.3 Stricture of the Fossa Navicularis with Redundancy

of Dorsal Penile Skin – 142 17.4 Results – 142

References – 143

17.1 Reconstruction of Acquired Meatal Stenosis and Strictures of the Fossa Navicularis

Transurethral resection procedures and early balanitis xerotica obliterans (BXO) have been associated with isolated strictures of the meatus and fossa navicularis.

In addition, anatomical anomalies or sequelae of ammo- niacal meatitis/balanitis can cause meatal stenosis in children. The choice of procedure for repair of acquired meatal stenosis is dependent on the anatomy of the ste- nosis and the penile skin. This chapter describes several procedures for reconstruction of the meatus and fossa navicularis using vascularized skin islands.

17.2 Reconstruction of Childhood Meatal Stenosis

Childhood meatal stenosis is usually the result of »fusi- on« of the meatus following irritation of the tip of the glans in the infant or young child in diapers. Also known

as ammoniacal meatitis, this condition is more frequent in the circumcised child. If identified acutely, parent edu- cation about the nature of the condition, more frequent diaper changes, and meatal dilations using a child/infant meatal dilator or tip of an ophthalmic antibiotic tube may allow resolution before meatal stenosis develops. The application of a topical steroid to the affected area and on the dilator is also helpful.

When the condition advances, ventral fusion can occur. Ventral fusion can be readily managed with eit- her a ventral meatotomy ( ⊡ Fig. 17.1 ) or a dorsal Y-V flap procedure ( ⊡ Fig. 17.2 ). A Y-V flap procedure is performed by elevation of a V flap from the dorsal glans tissue, creation of an incision through the stenotic area, and advancement of the V flap into the incision to widen the area of the stenosis. The Y-V flap procedure exchanges the redundancy of the dorsal glans tissue for the paucity of tissue at the stenotic meatus or distal fossa. It has been argued that this procedure is preferred over a ventral meatotomy, which could create a retrusive meatus. In our opinion, a ventral meatotomy provides better functional and cosmetic results as the desired slit

17

⊡ Fig. 17.2A–C. Y-V advancement for meatal stenosis. A A V-flap is outlined immediately dorsal to the stenosis.

B The area of stenosis is incised.

C The flap is advanced into the incision.

(From [11]) A B C

⊡ Fig. 17.1A–D. Ventral meatotomy as applied to ammoniacal meatal stenosis. A Local anesthetic is instilled into the obstructing tissue.

B The ventral diaphragm of tissue is compressed with a small hemo-

stat. C An incision is created through the tissue. D The creation of the ventral meatotomy. It is important to keep the skin edges separated during healing. (From [9])

A B C D

configuration of the meatus is often lost with the dorsal Y-V flap procedure.

17.2.1 Isolated Stricture of the Fossa Navicularis Following Transurethral Resection of the Prostate

Patients who present with an isolated meatal fossa strictu- re following transurethral resection of the prostate gene- rally gain little from repetitive dilations; however, reliable reconstruction of the meatus and fossa navicularis with nearly perfect functional and cosmetic results can be accomplished using several surgical techniques.

17.2.1.1 Y-V flap Procedures

Flap procedures for repair of true fossa navicularis stric- tures founded on the Y-V principle were described by Cohney [1] and Blandy [2]. Cohney’s procedure uses a ventral transverse peninsula flap, usually with ran- dom vascularity. The flap is transposed and interdigitated into the meatotomy, creating a retrusive meatus with a

»dog ear« at the transposition site ( ⊡ Fig. 17.3B ). Blandy’s modification creates a vertical skin peninsula flap on the midline of the penile shaft that is usually elevated with random vascularity and advanced into the meatotomy ( ⊡ Fig. 17.3A ). Although elevation with the fascial blood supply intact and elimination the »dog ear« are theoretic improvements over the Cohney procedure, the Blandy modification still leaves the patient with a coronal or distal shaft meatus. The functional results of both of these techniques are adequate when stenosis is confined to the fossa navicularis; however, both have been criticized due to their suboptimal cosmetic results.

A modification of Blandy’s procedure has been descri- bed by Brannen [3]. This procedure involves elevation of a peninsula flap based on the dartos fascial blood supply with aggressive advancement into the meatotomy defect ( ⊡ Fig. 17.3C ). Although the design of the longer flap was intended to place the meatus closer to the tip of the glans, most patients are left with a retrusive meatus and the unsightly appearance of shaft skin advanced into the ventral glans. Thus, in most cases, this modification yields neither a functional nor cosmetic improvement over Cohney’s or Blandy’s original flap designs.

Brannen’s procedure was then modified by DeSy, who used a longitudinal skin island mobilized on the dartos fascia and aggressively advanced it into the meatotomy defect by inverting the skin island ( ⊡ Fig. 17.3D ). Mobili- zed on a dartos fascial pedicle with the ventral glans fused ventrally over the dartos fascial strip, this procedure also requires a lengthy advancement of the midline dartos fas- cia. However, DeSy has reported excellent functional and cosmetic results [4].

17.2.2.2 Resurfacing of Fossa Navicularis

Devine reported a procedure he termed resurfacing the fossa navicularis, applicable to only short strictures confined to the intraglanular urethra [5]. This procedure involves excision of the strictured area with placement of a penile skin graft ( ⊡ Fig. 17.3E ). As an alternative, a tubed buccal mucosa graft could be used in lieu of a skin graft.

17.2.2.3 Transverse Ventral Penile Skin Island One of the authors of this chapter (GHJ) has described a procedure for reconstruction of the meatus and fossa navicularis that was intended primarily for strictures confined to the fossa navicularis [6], but can be used for structures up to 4.5 cm in length. Initially, a wide ureth- rostomy is created through the stenotic meatus and fossa down to the level of the normal urethra. The technique then involves elevation of a transverse ventral penile skin island on a broad ventral dartos fascial pedicle. The skin island is transposed and inverted into the meato- tomy defect. Although the broad dartos pedicle allows vigorous mobilization of the ventral fascial pedicle, it requires more aggressive dissection of the lateral glans flaps to assure a tension-free ventral glans fusion. The surgical technique for this procedure is described in detail below.

Evaluation with retrograde and voiding contrast medi- um and urethroscopy is performed in all surgical candida- tes. Urethroscopy is usually performed with a small, rigid pediatric cystopanendoscope. For patients in whom this is not possible but in whom contrast studies have indicated that the stenotic process is confined to the fossa, endosco- py is performed through the area of stenosis immediately after the urethrotomy is complete, to assure the surgeon that the stricture does not extend into the more proximal urethra.

The surgical approach is generally through the patient’s existing circumcision incision; in patients who have not been circumcised, it is via a partially circumci- sing incision on the ventral surface of the penis. The vent- ral penile skin and dartos fascia are elevated in the plane immediately superficial to the superficial lamina of Buck’s fascia and, in some cases, the ventral aspect of Buck’s fas- cia can be mobilized and included as the flap’s deep layer.

A grooved director is passed through the stricture and an external urethrotomy is made through the stricture in the fossa and extended approximately 1–1.5 cm into the normal urethra ( ⊡ Fig. 17.4 ).

The normal urethra is identified by bougienage and

endoscopy. The dimensions of the remaining glanular

epithelial strip are measured and a transverse skin island

is outlined on the ventral penile skin and tailored to

produce a 28- to 30-Fr neofossa navicularis. The island is

elevated to preserve the dartos fascial pedicle by incising

17

⊡ Fig. 17.3A–E. Techniques for correction of strictures of the ure- thral meatus and fossa navicularis. A Technique as described by Blandy. This utilizes a mid-line skin peninsula flap advanced into a meatotomy defect but creates a retrusive meatus. B Cohney’s technique (creation of a ventral transverse skin flap). C Brannen’s modification utilizing a more aggressive advancement of a mid-

line dartos-based peninsula flap. Note that penile skin is advanced onto the ventral glans. D DeSy’s technique. A longitudinal skin island is mobilized on dartos fascia, aggressively advanced, and inverted into a meatotomy. The ventral glans is then fused over the repair. E Resurfacing of the fossa navicularis as described by Devine.

(From[10])

A B

C D

E

or

the skin alone. The ventral penile skin is dissected from the fascial pedicle in the plane between the superficial fascial plexus and the deep subdermal plexus of the skin ( ⊡ Fig. 17.5 ). With the skin island oriented transversely, the broad dartos fascial pedicle is created from the entire

penile ventrum, and elevation of the fascial flap should be sufficient for a tension-free flap transposition.

The lateral glans flaps are dissected in the relatively avascular plane between the tips of the corpora caver- nosa and the glanular spongy erectile tissue. The small amount of bleeding that occurs during this dissection is easily controlled with bipolar electrocautery forceps and injection of the glans with diluted epinephrine. Tension or narrowing of the urethra of the glans caused by ventral fusion is avoided by wide elevation of the glans flaps, and the appearance of the glans after fusion is normal in most patients.

The skin island is transposed and inverted into the external urethrotomy defect without requiring aggressi- ve advancement of the ventral dartos fascia after elevati- on ( ⊡ Fig. 17.6 ). Flap transposition permits mechanically efficient mobilization of the fascia. The onlay is secu- red with tacking sutures (# 5-0 PDS with knots inside the urethral lumen) and a running subepithelial suture (#6-0 PDS).

The glans is closed ventrally over the neofossa with a #28-Fr sound through the area of reconstruction after the patch onlay is complete. A deep layer of #4-0 or

#5-0 monofilament absorbable suture and small (usu- ally #6-0) PGA sutures are used to bring the skin into everted apposition is used for glans closure. The sound is replaced with a small urethral stent. Suprapubic diver- sion was performed early in our series; however, some of our patients currently are diverted by placing a feeding

⊡ Fig. 17.4. The ventral transverse skin island as described by Jordan.

A urethrostomy defect is created to the level of normal urethra. The dimensions of the skin island is outlined transversely on the ventral penile skin. (From [11])

⊡ Fig. 17.5. The lateral glans wings are dissected. The skin island is then elevated on dartos fascia, transposed and inverted into the remaining dorsal midline strip (From [11])

⊡ Fig. 17.6. The skin island is sutured into the defect. Note the glans

wings have not been fused ventrally yet (From [11])

tube through a splent, to allow voiding (through the splent) on the 3rd postoperative day. The flap donor site is closed by transposition of the preputial skin into the defect and development of Burrow’s triangles to excise the small »dog ears« at the corners of the closure ( ⊡ Fig. 17.7 ).

17.2.3 Stricture Associated with Early Balanitis Xerotica Obliterans

Although BXO in children is normally seen with a redun- dant prepuce, phimosis and balanitis, it has been suggested that BXO begins as a perimeatal process. In patients with BXO who present early in the disease course with a meatal or fossa stricture, high intraurethral pressures appear to be generated during voiding, which leads to intravasation of urine into the glands of Littre. This intravasation may cau- se inflammation and microabscess formation, ultimately leading to a progressive and severe urethral stricture. It has been our experience that panurethral stricture disease is avoided if early aggressive reconstruction is offered to these patients while the stricture process is confined to the meatus or distal fossa navicularis.

While the meatus and fossa are generally the site of greatest functional limitation in BXO, the glanular skin is also a problem. Most patients will respond to topical steroids up to three times daily for 6–8 weeks, tapered to once daily. Generally after patients are reduced to a

once daily regimen, they begin to use it on an as-nee- ded regimen. In addition, BXO-associated inflammation seems to respond favorably to daily doxycycline. However, dermatologists commonly regard BXO as a premalignant condition, and a biopsy is therefore recommended in patients with BXO, who do not respond as expected to treatments, as squamous cell carcinoma may present with what appears to be severe BXO of the glans.

In addition to the one-staged procedures described above for strictures of the fossa navicularis, some sur- geons prefer a staged approach for reconstruction of the fossa navicularis in BXO. Devine’s procedure (i.e., resur- facing of the fossa navicularis) has been used for BXO, and when there is concern that the BXO would recur involving the graft, a tubed buccal mucosa graft could be used alternately. Another application would be to place a buccal graft open as a first stage followed by a second stage in which the graft is tubed [7].

17.3 Stricture of the Fossa Navicularis with Redundancy of Dorsal Penile Skin

Occasionally a patient will present with stenosis of the fossa navicularis or distal urethral stricture disease, who has redundant skin on the dorsum of the penis. This can be reconstructed using a transverse skin island elevated on the dorsal dartos fascia from the redundant dorsal skin, with the deep dissection in the layer immediately superficial to the outer lamina of Buck’s fascia [8].

To produce a tension-free fusion of the glans around the neomeatus and neofossa navicularis, the dorsal trans- verse island procedure requires wide elevation of the lateral glans flaps similar to the other techniques descri- bed above. Some patients, particularly those who have undergone multiple procedures, do not have enough redundancy to elevate a dorsal transverse island without torsion. However, in most cases the torsion resolves over time, and leaving some torsion in exchange for a good functional result is generally acceptable. If the surgeon suspects in advance that this might occur, the patient should be informed before the surgery is performed.

17.4 Results

Several procedures for reconstruction of true strictures of the fossa navicularis provide excellent aesthetic and functional results. The largest series of patients in which a single technique has been used for reconstruction of the fossa navicularis was reported by DeSy, using a lon- gitudinally oriented skin island mobilized on the dartos fascia. The ventral transverse island technique has also been used in large numbers by several reconstructive surgeons, including the author, with excellent results.

17

⊡ Fig. 17.7. The appearance of the glans when re-fused ventrally with

the flap harvest site closed (From [11])

References

1. Cohney BC (1963) A penile flap procedure for the relief of meatal strictures. Br J Urol 35:182

2. Blandy JP, Tresidder GV (1967) Meatoplasty. Br J Urol 39:623 3. Brannen GE (1976) Meatal reconstruction. J Urol 116:319–321 4. DeSy WA (1984) Aesthetic repair of meatal stricture. J Urol

132:678–679

5. Devine CJ Jr (1986) Surgery of the urethra. In Walsh PC, Gittes RF, Perlmutter AD et al (eds) Campbell’s Urology, edn 5. WB Saunders, Philadelphia, p 2853

6. Jordan GH (1987) Reconstruction of the fossa navicularis. J Urol 138:102–104

7. Venn SN, Mundy AR (1998) Urethroplasty for balanitis xerotica obliterans. Br J Urol 81:735–737

8. Duckett JW (1981) The island flap technique for hypospadias repair. Urol Clin North Am 8:503–511

9. Jordan GH, Schlossberg SM (2002) Surgery of the penis and ure- thra. In Campbell’s Urology, 8

Edn. Vol 4, Chap. 110, Saunders, Philadelphia

10. Jordan GH (1987) Management of anterior urethral stricture disease. problems in urology, Vol 1. Philadelphia, JB Lippincott 11. Jordan GH (1999) Reconstruction of the meatus-fossa navicu-

laris using flap techniques. In: Schreiter F, Bartsch (eds) Plas-

tic-Reconstructive Surgery in Urology. George Thieme, Stuttgart,

1999