Page 52 - Read Online

Page 2 of 10 Joshi et al. Plast Aesthet Res 2022;9:22 https://dx.doi.org/10.20517/2347-9264.2021.98

[1]
common cause of injury is road traffic accidents . While in the Western world PFUI is uncommon and its
incidence is decreasing due to higher safety standards on the roads and at work, in developing countries,
due to lack of safety rules and uncontrolled environment such as obligation to wear the helmet on road or at
work, fasten seat belts, etc., PFUIs are more common and are usually related to work accidents, traffic
accidents, falls from high places, or natural catastrophes . The site of urethral injury is the bulbo-
[2]
membranous junction in the majority of patients. Rarely, the urethral injury is localized to the prostato-
membranous junction, intra prostatic, and/or at the bladder neck. Step-wise anastomotic urethroplasty, as
[3]
described by Webster in 1986, remains the gold standard for treatment of PFUI . The goal of the approach
is to reach a tension free anastomosis between the two ends of healthy urethra after transecting the fibrotic
segment. The progressive perineal approach is the preferred surgical method. In complex patients with long
fibrotic segments or double urethral injuries, the transabdominal approach is also utilized to allow a more
extensive pubectomy and expose the prostatic urethra and the bladder neck. Bulbar urethral ischemic
necrosis (BUIN) is an iatrogenic entity which results from previous failed anastomotic repairs in patients
with PFUI. The term BUIN was used for the first time in 1986 by Turner-Warwick . Historically, BUIN
[4]
[5,6]
was defined as “long gap” or “unsalvageable” bulbar urethra after previous failed repairs . To date, an
accepted and standardized definition of BUIN is lacking.

Anatomical considerations
The male urethra is generally classified into two portions: (1) the posterior urethra that extends from the
bladder neck to the external urinary sphincter and comprises the prostatic urethra and the membranous
urethra; and (2) the anterior urethra, which comprises the pendulous urethra (or penile) and the bulbar
urethra, beginning at the peno-scrotal junction and ending at the bulbo-membranous junction.

The bulbar urethra can be divided into distal, mid, and proximal portions. The proximal and mid portions
are unique as the spongious tissue is more developed in this region. These segments are also covered by the
bulbospongiosus muscle that plays an important role in micturition and ejaculation. The proximal two-
thirds of the muscle is circumferential around the urethra. The distal one-third of bulbospongio-cavernous
[7]
muscle surrounds the corpus cavernous at the base of the penis .

Antegrade blood supply to the urethra is derived from the bulbar arteries and perforating vessels of the
cavernosal arteries. Retrograde blood supply is derived from the dorsal penile artery. The urethra is also
supplied laterally by the circumflex vessels. All these branches are derived from the internal pudendal
arteries, which come from the anterior division of the internal iliac arteries.

“Our” definition of BUIN
BUIN is defined as a compromised or complete absence of a segment of bulbar urethra. It can appear as a
long narrowing or semi-obliteration of a segment of the bulbar urethra (bulbar urethral fibrosis), or the
absence of a segment of bulbar urethral at the retrograde and/or micturition urethrograms (RGU, MCU).
The etiology is always vascular.

Pathophysiology of BUIN
On routine retrograde urethrogram, BUIN usually appears as a long bulbar urethra stenosis or as a
complete loss of bulbar urethra. For both cases, the etiology of the pathologic condition is vascular ischemia.

In 1986, Turner-Warwick described the causes for this vascular ischemia and spongionecrosis.