Cadaveric Urethra? A novel technique of male urethral

Cadaveric Urethra? A novel technique of male urethral
transplantation.
Poster No.:
C-1636
Congress:
ECR 2016
Type:
Educational Exhibit
Authors:
G. O. R. D. Rego , A. Kanas , W. Kawakami , F. Yamauchi , A.
1
2
2
2
2
2
2 1
Fazoli , L. Ribeiro-Filho , R. Baroni ; Sao Paulo, Sao Paulo/BR,
2
Sao Paulo/BR
Keywords:
Trauma, Transplantation, Biological effects, Cystography /
Uretrography, Contrast agent-other, Fluoroscopy, Conventional
radiography, Urinary Tract / Bladder, Genital / Reproductive
system male, Abdomen
DOI:
10.1594/ecr2016/C-1636
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Page 1 of 18
Learning objectives
•
•
•
•
Introducing the technique of transplantation using acellular matrices from
cadaveric urethras;
Reviewing the main indications for this procedure and important information
on pre-operative cystourethrography;
Evaluating postoperative images after urethral transplantation procedure;
Illustrating common complications of the procedure.
Background
Cystourethrography (CUG) remains an important tool in the evaluation of urethral
strictures (length, location and caliber) and assess the functional significance of the
stricture. Despite the advent of newer imaging methods, CUG remains a cornerstone
in the management of urethral stricture disease, given its efficiency, availability and low
cost.
Although relatively common, male urethral stricture has poorly effective treatments. The
use of acellular matrices on cadaveric transplants for urethral reconstruction arises as a
promising clinical reality over the last decade. Although rarely performed, radiologists get
familiar with the procedure, important preoperative information and main complications
on CUG.
ANATOMY
Male urethra is a single tubular structure composed by several heterogeneous segments:
prostatic, membranous and spongy urethra. Each part has distinguished characteristics.
The membranous is firmly fixed to the ischio and pubis, rendering this portion of
the urethra susceptible to disruption with pelvic fractures. The spongy is located
concentrically within the corpus spongiosum and is divided into bulbar and pendulous
segments. Blunt straddle injury to the perineum, for instance, is often a common cause
of bulbar strictures. Both membranous and spongy urethras are lined with stratified
columnar and pseudostratified epithelium. Stratified squamous epithelium is seen distally
close to the meatus.
It is extremely important for radiologists identify and evaluate the portions of the urethra
and its main features (fig. 1).
Page 2 of 18
URETHRAL STENOSIS
The male urethral stricture is a narrowing of the urethra due to scar tissue, which leads
to obstructive voiding dysfunction with potentially serious consequences for the entire
urinary tract. Its prevalence among men in industrial countries is estimated at 0.9%. This
disease has the potential for great negative impact on patients. Most urethral strictures
are the result of infection (fig. 2), instrumentation, or other iatrogenic causes. In the
industrialized world, strictures are commonly caused by external trauma (fig. 3) and
instrumentation, whereas in less developed areas infectious strictures continue to be
more common.
SURGERY AND URETHRAL TRANSPLANT
Currently there are several techniques for urethral stenosis correction, regardless of
underlying cause: classical urethroplasty, use of stents (fig. 4) and urethral transplant.
Although classic urethroplasty appears as the main procedure for correction of this
problem, skin flaps and buccal mucosa grafting may not be used for long and complex
strictures. In the quest for an ideal urethral substitute, autologous transplantation of
different tissues have been tried. Unfortunately, results of these numerous creative
attempts were disappointing. On this context, the use of acellular matrices (fig. 5) on
cadaveric transplants for urethral reconstruction (fig. 6, 7) arises as a promising clinical
reality. Acellular scaffolds, which are produced by enzymatic conversion of human
cadaveric urethras and bladders with a protocol based on the use of DNAses have
demonstrated the ability to induce tissue regeneration layer by layer.
URETHROCYSTOGRAPHY
CUG that consists in the opacification of the urethra and bladder using an iodized solution
and pouring it through the urethra and into the bladder is the current gold standard for
accurate diagnosis, staging, delineation of urethral strictures (stricture length, location
and caliber) and assess the functional significance of the stricture. Despite the advent
of newer imaging methods, CUG remains a cornerstone in the management of urethral
stricture disease, given its efficiency, availability and low cost.
Important features of preoperative CUG (fig. 8A, 9, 11) and postoperative findings (fig.
8B, 10, 12, 13) are illustrate.
Page 3 of 18
Images for this section:
Page 4 of 18
Page 5 of 18
Fig. 1: Urethral anatomy.
© Radiologia e Diagnóstico por Imagem, Instituto de Radiologia e Diagnóstico por
imagem da Faculdade de Medicina da USP, Hospital das Clinicas da Faculdade de
Medicina da Universidade de São Paulo - Sao Paulo/BR
Page 6 of 18
Fig. 2: Acute urethritis. Irregularity of all segments of the urethra which can progress to
complications such as stenosis.
© Radiologia e Diagnóstico por Imagem, Instituto de Radiologia e Diagnóstico por
imagem da Faculdade de Medicina da USP, Hospital das Clinicas da Faculdade de
Medicina da Universidade de São Paulo - Sao Paulo/BR
Fig. 3: Patient after urethral trauma. Posterior urethra not opacified during voiding effort.
Anterior urethra is normal. Urinary bladder shows normal aspect, opacified via cystotomy.
© Radiologia e Diagnóstico por Imagem, Instituto de Radiologia e Diagnóstico por
imagem da Faculdade de Medicina da USP, Hospital das Clinicas da Faculdade de
Medicina da Universidade de São Paulo - Sao Paulo/BR
Page 7 of 18
Fig. 4: Stent located in the penile urethra with distal tapering. Previous of transurethral
resection of the prostate.
© Radiologia e Diagnóstico por Imagem, Instituto de Radiologia e Diagnóstico por
imagem da Faculdade de Medicina da USP, Hospital das Clinicas da Faculdade de
Medicina da Universidade de São Paulo - Sao Paulo/BR
Page 8 of 18
Fig. 5: Biological acellular matrix urethral grafting (cross sections). The rationale for
onlay/inlay procedures. A. The arrows indicate the direction of the cellular ingrowth. B. If
this rule is observed, then the matrix will induce proper regeneration of the urethral wall.
© Departamento de Urologia da Faculdade de Medicina da USP, Hospital das Clinicas
da Faculdade de Medicina da Universidade de São Paulo - Sao Paulo/BR
Page 9 of 18
Fig. 6: Urethral ressection. A. The urethra is removed from the cadaveric donator by a
perineal incision. B. Block dissection of bladder, prostate and urethra.
© Departamento de Urologia da Faculdade de Medicina da USP, Hospital das Clinicas
da Faculdade de Medicina da Universidade de São Paulo - Sao Paulo/BR
Page 10 of 18
Fig. 7: Surgical technique. A. Degloving penis. B. The stenotic urethra is incised
longitudinally. Note the boundary between normal and fibrotic urethra. C. Urethral meatus
advancement to avoid exposure of the matrix to the environment. D. Implant of urethral
acellular matrix graft with continuous suture. E. 15 cm urethra are transplanted. F.
Catheter and antibiotics for one month. No need for immunosuppressants.
© Departamento de Urologia da Faculdade de Medicina da USP, Hospital das Clinicas
da Faculdade de Medicina da Universidade de São Paulo - Sao Paulo/BR
Page 11 of 18
Fig. 8: Urethroctstography. A. Preoperative. B. Postoperative - Full integration of the graft
with the receptor urethra.
© Departamento de Urologia da Faculdade de Medicina da USP, Hospital das Clinicas
da Faculdade de Medicina da Universidade de São Paulo - Sao Paulo/BR
Fig. 9: Urethral trauma.Preoperative - Multiple irregular filling defects in the middle and
distal thirds of the penile urethra.
Page 12 of 18
© Radiologia e Diagnóstico por Imagem, Instituto de Radiologia e Diagnóstico por
imagem da Faculdade de Medicina da USP, Hospital das Clinicas da Faculdade de
Medicina da Universidade de São Paulo - Sao Paulo/BR
Fig. 10: Urethral trauma. Postoperative - tx complication: fistula.
© Radiologia e Diagnóstico por Imagem, Instituto de Radiologia e Diagnóstico por
imagem da Faculdade de Medicina da USP, Hospital das Clinicas da Faculdade de
Medicina da Universidade de São Paulo - Sao Paulo/BR
Page 13 of 18
Fig. 11: Posterior urethra not opacified. Anterior urethra is normal.
© Radiologia e Diagnóstico por Imagem, Instituto de Radiologia e Diagnóstico por
imagem da Faculdade de Medicina da USP, Hospital das Clinicas da Faculdade de
Medicina da Universidade de São Paulo - Sao Paulo/BR
Page 14 of 18
Fig. 12: Postoperative. Urethra with reduced caliber, but pervious.
© Radiologia e Diagnóstico por Imagem, Instituto de Radiologia e Diagnóstico por
imagem da Faculdade de Medicina da USP, Hospital das Clinicas da Faculdade de
Medicina da Universidade de São Paulo - Sao Paulo/BR
Page 15 of 18
Fig. 13: Postoperative - transplantation complication: focal stenosis of the anastomosis.
© Radiologia e Diagnóstico por Imagem, Instituto de Radiologia e Diagnóstico por
imagem da Faculdade de Medicina da USP, Hospital das Clinicas da Faculdade de
Medicina da Universidade de São Paulo - Sao Paulo/BR
Page 16 of 18
Findings and procedure details
A digital x-ray was performed and the iodized contrast medium was used. The surgery
was done by the urology service of Hospital das Clínicas da Faculdade de Medicina da
Universidade de São Paulo - Brasil.
Conclusion
This pictorial essay aims to demonstrate the use of cadaveric urethra as a viable
alternative for the treatment of male urethral stenosis, showing the pre and post operative
images on cystouretrogaphy and highlighting the main points a radiologist should
observe.
Personal information
References
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