Urethroplasty - Ventral Onlay

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In the bulbar region the urethra lies dorsally in the corpora spongiosa. It is possible for us to use the buccal mucosa graft as a ventral onlay and then overclosed the spongiosa to cover the BMG.

Indications

Same as Barbagli’s urethroplasty, suitable for obese patients, proximal bulbar strictures, failed dorsal onlay buccal mucosa graft.

Procedure

Under spinal anesthesia through a midline perineal incision the bulbar urethra is exposed but not mobilized. Methylene Blue dye is injected through the meatus into the proximal urethra. A dilator is passed through the meatus upto the level of the stricture. The bulbar urethra is opened ventrally distal to the stricture. Ventral urethrotomy is performed through the strictured urethra into normal proximal bulbar urethra upto 1.5cm. Methylene Blue stained urethral mucosa helps to identify the narrowed lumen of the urethra. A 1.5cm wide and 6cm long BMG is harvested from the chic and defatting is performed. The BMG is sutured to the urethral mucosa with continuous sutures of 4/0 vicryl on the right side. The mucosal surface of the BMG faces inside towards lumen of the urethra. Then a 14 F silastic Foley catheter is inserted to the bladder. Then the left side of the urethra is sutured to the buccal mucasa with continuous sutures. The corpora spongiosa is over closed with continuous sutures of 4/0 vicryl and taking bite of the buccal mucosa graft.  The wound is closed in layers. The catheter is removed after three weeks.

BMG

  1. The best place to take a 1.5cm wide and 6 cm long BMG is from the inner side of the cheek. 
  2. Alternately lower lip mucosa can be used.  It is thinner than the cheek so it is useful for the ASOPA technique and for the glance urethra.  
  3. Mucosa can be harvested from the floor of the mouth.  The characters are same as lower lip mucosa.

Lingual Mucosa Graft

Recently surgeons have started using lingual mucosa from lateral edge of the tongue.

Skin-prepucial, penile, scrotal, Post auricular Wolf Graft(PAWG), SIS, Bioengineered Tissue

Skin-prepucial – whenever urethra needs replacement (substitution) pedicled prepucial skin tube is the first choice.  Harvesting of the inner prepucial skin with its blood supply is performed as described by Asopa and Ducket.  A stay suture is taken through the glans dorsal to the meatus.  A circumcision incision is made on the inner layer of the prepuce 5mm away from the coronal sulcus.  This incision is depend upto the Bucks facia at this level the whole penis is degloved upto the base.   This dissection leaves the dorsal neurovascular bundle intact on the penis.  A second incision  is made on the outer surface of the prepuce at the level of the glans.  Here the penile skin is degloved again just below the skin.  Now the prepuce with its blood supply forms a circular tube between the penile skin and the Bucks facia.  This prepucial skin plus facia tube is incised at 6 O’clock towards the base of the penis.  Now stay sutures are taken at the junction of the inner and outer prepucial skin at both ends.  An incision is made with sharp scissors between these two skin layers.  The outer skin can be used as a free graft or as a pedicled graft if required.  But most of the times, it is discarded.  The inner prepucial skin with its blood supply is rotated around the penile base and is used to form a tube around a 14 Foley catheter.  Now this tube is anastomosed proximally and distally to the urethra.  The most common use is for bulbar urethral necrosis following posterior urethral trauma.  The proximal end of the prepucial tube is anastomosed apex of the prostatic urethra.  The distal end is anastomosed to the urethra at the level of distal bulbar portion.  The disadvantage of pedicle prepucial tube is that it forms a diverticulam and leads to post micturition dribble.  The patient may get anastomotic stricture at both ends of the prepucial tube. 

Penile Skin – the next best choice after prepucial skin is penile skin.  It is used routinely for the Orandi’s urethroplasty. 

Scrotal Skin – is the last choice for urethral substitution.  Scrotal skin is thermo labile so it forms a diverticulam once it is turned inside.  As it is hair bearing skin (hirsute) it leads to hair ball and stone formation.  The skin also becomes soggy as the washerman’s feet are. Scrotal skin is used for Turner Warwick scrotal drop back procedure urethroplasty.  Scrotal skin is also used for Blandy – Manmeet Singh urethroplasty. 

Post Auricular Wolf Graft (PAWG) – is the skin of choice in patients of BXO where buccal mucosa is not suitable for grafting as the donor site is hidden behind the ears.

SIS – small intestinal submucosa is available as off the shelf replacement for the urethra.  SIS provides scaffolding over which the urothelium grows and the SIS is slowly absorbed.  I have used SIS for full length urethroplasty in 12 patients.  All patients developed restricture.  So at the present time, we have stopped using SIS as a substitute for urethroplasty. 

Bio Engineered Tissue – with the recent advances in regenerative medicine many labs are developing urethral substitutes in the lab.       

Appendix, Rectal Mucosa, Tunica Vaginalis

Appendix – an article was published by Mitrofanoff on the use of appendix for replacement of urethra.  A careful appendicectomy is performed without damaging the appendix.  The outer peritoneal layer is removed with sharp dissection.  the appendix is incised longitudinally.  The mucosa of the appendix is carefully excised.  The appendicular sub mucosa is now used as a free patch to augment or substitute the urethra.  I have used this technique in two patients with gratifying results in desperate situations where options of urethral replacement tissue are limited.

Rectal Mucosa – there are few published reports mostly from China regarding use of rectal and colonic mucosa for reconstruction of long segments of the urethral strictures.  I have not used this method till today.

Tunica Vaginalis – I have used the tunica vaginalis in two patients where they had simultaneous hydrocele. The hydrocele sack is opened as in hydrocele repair and part of the tunica vaginalis is rotated to be used as a dorsal onlay graft urethroplasty. Though the patients did well post operatively, I do not favor this option.