Operative Techniques

A certain number of new techniques and modifications continue to be published every year. However, a certain number of methods are no longer presented in meetings and conferences - although they have been used for many years - and will eventually disappear from the current bibliography.

The MAGPI procedure carried out in 1,111 children [5] is only one of the numerous examples. One possible explanation is the human factor. If after an initially successful start the number of complications increases and the conceptual error becomes evident, the authors may hesitate to publish these results in the same journal as the original paper. One of the classic examples is the first successful bladder substitution using isolated ileum segments, which was published in the Centralblatt fuer Chirurgie in 1888 by Tizzoni and Foggi (whose name was actually Poggi). Both of them are still mentioned worldwide as pioneers in the current literature, even though their experiments carried out on healthy dog bladders were fundamentally faulty because self- regeneration of the residual bladder occurred within in the following year. The ileum segment found to be a useless diverticulum located on the dome of the bladder by Schwarz, was published later in the almost unknown Journal of the University of Bologna in Italian and was never mentioned in the international literature [20].

Many different techniques and modifications have been developed in order to overcome the high number of postoperative complications and the incidence of unsatisfactory outcomes. However, the true incidence of »hypospadia cripples« who started with a meatal anomaly in early childhood remains unknown. Nevertheless, within the broad spectrum of pathology found in our cohort of patients admitted for urethral reconstruction, about one-third were operated on more or less often for an originally congenital penile anomaly.

Up to 1990, one-stage urethral reconstruction was performed mainly using full-thickness skin flaps; transverse island flaps in the form of tubes [4] are onlays and two-stage repair is done with penile skin flaps.

In contrast to other institutions, the split skin grafts were used only for the two-stage mesh-graft technique - mainly for hypospadia cripples - or in order to cover penile skin defects as large as 12-10 cm. Interestingly, the thin split-skin grafts taken by a dermatome (3/10 mm) turned out to be an excellent material and the healing process was always perfect as long as the graft itself could be placed on the well-vascularized flaps of the superficial fascia (Scarpa or dartos) placed around the corpora cavernosa.

□ Fig. 6.4. Stripping down of the shaft skin together with Scarpa's fascia after coronal incision. Adapted from R. Hohenfellner, Ausgewählte urologische OP-Techniken, 2. Auflage Thieme-Verlag, 1997

□ Fig. 6.6. Lifting of the urethra off the underlying tissue. Adapted from R. Hohenfellner, Ausgewählte urologische OP-Techniken, 2. Auflage Thieme-Verlag, 1997

□ Fig. 6.5. Dorsally freed bundle. Adapted from R. Hohenfellner, Ausgewählte urologische OP-Techniken, 2. Auflage Thieme-Verlag, 1997

□ Fig. 6.7. Sharp dissection of the lateral cord bands to both sides of the urethral bed after placement of two vessel loops. Adapted from R. Hohenfellner, Ausgewählte urologische OP-Techniken, 2. Auflage Thieme-Verlag, 1997

□ Fig. 6.8. Outlining of the graft from the lip and possibly the inner cheek. Submucous injection (1:100,000 adrenaline) facilitates dissection of the graft. Adapted from R. Hohenfellner, Ausgewählte urologische OP-Techniken, 2. Auflage Thieme-Verlag, 1997
□ Fig. 6.9. Suturing of the onlay graft to the plate after lateral dissection of the penile shaft skin. Adapted from R. Hohenfellner, Ausgewählte urologische OP-Techniken, 2. Auflage Thieme-Verlag, 1997

This strategy also reflected the trend of the one-stage onlay repair with transverse island flaps taken from the inner preputial layer and placed ventrally on the preserved urethral plate [1]. This was in strong contrast to the former technique - introduced in 1982 and used up to 1987 - where the chordee was resected together with the urethral plate and substituted by a tube in form of a neourethra constructed also from the inner layer of the prepuce [4]. Nevertheless, it took almost 12 years until the tube was replaced by an onlay flap with no data on the high number of fistulas and obstructions found by others mainly on the side of the end-to-end anastomosis [1]. However, the main problem of a transverse island flap is how to preserve vascularization.

A wide spectrum of anatomical variations is found by intraoperative illumination of the axial vessels located within the superficial fascia [18]. Therefore a certain number of flaps may end up as a graft, which is better tolerated as an onlay, instead of a tube rotated for 90° and anastomosed end-to-end later on.

Hendren stated that »a free graft covered by two layers of well-vascularized tissue works as well, if not better, than a pedicle flap« and in accordance with our own experience with buccal mucosa grafts, we believe that he was right. In addition, secondary vascularization of a graft - mostly from vessels arriving from outside - is guaranteed if all the connective tissue is removed or if a split-skin graft is used. Therefore, thinner grafts can be larger and thereby facilitate a successful tissue defect substitution.

As stated before, in reconstructive surgery the basic principle of free tissue transfer is quite simple and logical: there must be close homology between the replaced tissue and the material used for reconstruction. Nevertheless, it took almost 100 years to raise the question of how well skin works over the long term in urethral replacement. Sir Richard Turner Warwick stated that skin hates urine, because »every year, between 1 and 2% of my former successful urethroplasties are lost mainly by secondary strictures.«

In addition to lanugo hair follicles - hard to identify in early childhood! - sebaceous and sweat glands are located in the penile and scrotal skin mainly used as onlay flap or tubes for urethral reconstruction in early childhood. Therefore, local inflammations surrounding the ducts of these glands is a common finding in ure-throscopy in adults caused by recurrent infection or secondary strictures.

However, it still remains unclear why secondary ure-thral obstructions occur sometimes suddenly after many years following successful reconstruction, in one of our cases, as late as 18 years later.

In animal experiments, Filipas et al. [10] from our institution implanted full skin grafts and buccal mucosa grafts in the bladder of female Irish mini pigs. Perfect wound healing without tissue shrinkage was observed in the buccal mucosa grafts. In contrast, shrinkage up to 30%, severe inflammation, and stone formation occurred in the implanted full skin grafts.

In immunohistochemical investigations, expression of cytokeratin 20 (usually not expressed in the original buccal mucosa) was similar between the urothelium and all buccal mucosa grafts but not in the full skin grafts transplanted in the bladder.

Therefore, the advantages of buccal mucosa in comparison with full skin grafts were also demonstrated in animal experiments. However, today the onlay island flap taken from the inner layer of the prepuce is still used worldwide in the one-stage hypospadia repair. The same is true for the Snodgrass technique, although the final outcome remains open. As mentioned before, long-term observations are necessary. Studies to prove the usefulness of the dorsal incision through the ure-thral plate (comparable with the Sachse procedure) will stand [11].

One of the disadvantages of the otherwise gold standard end-to-end anastomosis in posttraumatic membranous strictures is the risk of postoperative penis shortage in the more extensive strictures. Using a buccal mucosa graft, a one- or two-stage procedure can help to overcome this problem [17], the current strategy for primary hypospadia repair in Mainz in 2002 [7]. Since 1990, our strategy has not changed. As mentioned before, esthetic corrections are not recommended and also not performed in our institution.

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