Dorsal vs. Ventral Buccal Graft Dorsal vs. Ventral Buccal Graft

Urethral strictures affect 1% of men and are rare in women. Most urethral strictures in the
United States develop in the bulbar section of the urethra which is the section of the
urethra proximal to the penis but distal to the prostate. A common method of surgical
correction is to longitudinally open the strictured urethra and augment its width by the
addition of a graft of buccal mucosa taken from the oral cavity. The urethrotomy for
placement of the graft can be made along the superficial (ventral) or deep (dorsal) side of
the urethra. The graft bed dorsally is the tunica albuginea of the corporal bodies (the
capsule around the erectile bodies of the penis) whereas ventrally it is the corpus
spongiosum of the urethra (the vascular layer that surrounds the urethra).

Ventral buccal graft onlay first described by Morey and McAninch in 1996, involves a midline
perineal incision and retraction of the bulbo-spongiosum muscle downward to expose the
ventral urethral surface. The corpus spongiosum is incised longitudinally to expose the
urethral lumen and the incision is extended proximal and distal to the established stricture.
The buccal mucosa graft is harvested and trimmed to the length and width of the urethrotomy
and the graft is sutured at the proximal and distal apices and a running suture at the
lateral margins to establish a tight anastomosis. Ventral placement allows for limited
urethral mobilization and easy access but there is concern about higher likelihood of
diverticulum formation and development of associated complications such as post-void
dribbling and ejaculatory dysfunction. In addition, many surgeons have concern about graft
contraction as spread-fixating the graft is not possible.

Dorsal buccal graft onlay, first described by Barbagli in 1996, also involves a midline
perineal incision. The bulbo-cavernosum and corpora cavernosum are dissected from the bulbar
urethra allowing for complete mobilization of the urethra. The urethra is rotated 180 degrees
to allow for dorsal access and an incision is made on the dorsal urethra proximal and distal
to the stricture location. The buccal graft is harvested and trimmed to the appropriate size
of the urethrotomy and spread on the overlying tunica albuginea of the corporal bodies. The
right mucosal margin of the urethra is sutured to the right margin of the buccal graft and
the corporal bodies. The urethra is rotated back to allow for suturing of the left mucosal
margin to the left margin of the buccal graft and corporal bodies, essentially covering the
entire urethral plate. Dorsal placement potentially allows for a more stable vascular bed for
graft sustainability and less spongiosal bleeding, but requires a greater urethral
mobilization and longer operative times. The technical challenge of graft placement in a
dorsal location is much greater than placement ventrally. Potential problems with dorsal
placement include damage to the male external urinary sphincter, which is dorsally located,
and anastomotic leakage and perineal abscess in the immediate post-operative period.

There are multiple studies that attempt to compare the outcomes of ventral versus dorsal
graft placement for bulbar urethroplasty, but these studies rely on case series and
retrospective data. Andrich and Mundy reported better outcomes with dorsal buccal placement,
but statistical significance was not formally established. Both Barbagli and Figler were
unable to demonstrate superiority of either ventral or dorsal buccal graft placement.
Currently there is no high level of definitive randomized evidence to suggest superiority of
either ventral or dorsal buccal placement in terms of patient outcomes and complications. In
fact, the best level of evidence is VI (small case series) and dorsal vs. ventral placement
is largely dependent on individual clinical judgment and comfort level with each procedure.

One factor contributing to the inability to detect a difference between dorsal vs. ventral
graft placement has been the liberal definition of success that leads to uniformly high
success rates across studies (85-95%) and, hence, studies that are underpowered to detect a
difference in success rates. In these studies, the definition of success has typically been
"need for repeat surgery". Such a definition suffers from significant detection bias in that
(1) subclinical stricture recurrences may go undetected if they are not screened for; and (2)
surgeon or patient reluctance to undergo a repeat surgery may lead to false negatives. When
patients are rigorously followed with endoscopic inspection of the area of surgery with
cystoscopy, narrowing is often identified at a much higher rate than "need for repeat
surgery". For instance, in a preliminary review of our retrospective data using surveillance
cystoscopy, the investigators detected narrowing in 46% of ventral buccal patients and
approximately 18% of dorsal buccal patients. This more strict definition of success and the
lower success rates that follow may allow for detection of a clinically meaningful difference
in the success rate with the two procedures in a reasonably-sized clinical trial.

The investigators plan a randomized comparison of dorsally-placed vs. ventrally-placed buccal
mucosa graft in men undergoing buccal graft urethroplasty for bulbar urethra stricture. A
collaborative multi-institutional study deriving data from the Trauma and Urologic
Reconstruction Network of Surgeons, a network of twelve reconstructive urology centers in the
United States, would allow the investigators to achieve the required sample size within 2-3
years. The results of this study will ultimately advance research efforts in urethral
stricture management and provide substantial evidence for utilization of ventral versus
dorsal buccal placement for reconstructive urologists.

Inclusion Criteria:

- Strictures must predominantly include the proximal and/or mid bulbar urethra and be
otherwise amenable to buccal graft onlay urethroplasty

- Strictures may extend from the mid-bulbar urethra up to the distal bulbar urethra
within the scrotum, but not through the scrotum to the pendulous junction

- Subjects able to consent for themselves

Exclusion Criteria:

- prior open urethral surgery, such as prior urethroplasty, artificial urinary sphincter
placement, male urethral sling placement, and rectourethral fistula

- radiation therapy to the pelvis

- previous hypospadias repair

- lichen sclerosis unable to consent for themselves