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THE URINARY BLADDER
1
‫عبدالرزاق السلمان‬.‫د‬
SURGICAL ANATOMY • It is lined by transitional epithelium
covering the connective tissue lamina propria, which contains a
rich plexus of vessels and lymphatics.
• When the detrusor muscle hypertrophies, the inner layer,
covered by urothelium, stands out, resulting in the appearance of
trabeculation.
• Over the trigone is a thin layer of smooth muscle to which the
epithelium is closely adherent and which extends as a sheath
around the lower ureters and into the proximal urethra.
• Around the male bladder neck is the smooth muscle internal
sphincter innervated by adrenergic fibres, which prevents
retrograde ejaculation.
• The distal urethral sphincter is a horseshoe-shaped mass of
striated muscle that lies anterior and distal to the prostate, or in
the proximal two-thirds of the female urethra. It is distinct from
the pelvic floor and is supplied by S2–S4 fibres via the pudendal
nerve and by somatic fibres passing through the inferior
hypogastric plexus.
Arteries
The superior and inferior vesical arteries are derived from the
anterior trunk of the internal iliac artery. Branches from the
obturator and inferior gluteal arteries (and from the uterine and
vaginal arteries in females) also help to supply the bladder.
Veins
The veins form a plexus on the lateral and inferior surfaces of the
bladder. In the male the prostatic plexus is continuous with the
vesical plexus, which drains into the internal iliac vein. In the
female similar large veins are continuous with the vaginal plexus.
Lymphatics
These accompany the veins and drain to nodes along the internal
iliac vessels and then to the obturator and external iliac
chains.Some lymphatics pass to nodes that are situated posteriorly
to the internal iliac artery (hypogastric nodes).
INNERVATION :
The parasympathetic input
This is derived from the anterior primary divisions of the second,
third and fourth sacral segments (mainly S2 and S3). Fibres pass
through the pelvic splanchnic nerves to the inferior hypogastric
plexus, from where they are distributed to the bladder. The pelvic
plexus can be damaged during deep pelvic operations.
The sympathetic input
This arises in the 11th thoracic to the second lumbar segments;
fibres pass via the presacral hypogastric nerve (rather than via the
sympathetic chains) to the inferior hypogastric plexus.
Somatic innervation
A somatic innervation passes to the distal sphincter mechanism via
the pudendal nerves and also via fibres that pass through the
inferior hypogastric plexus.
Functional aspects
Sympathetic nerves convey afferents from the fundus. Afferents
arise from the mucosa, where they respond to touch, temperature
and pain, and from the detrusor and lamina propria, where they
convey stretch information. Afferents pass via the inferior
hypogastric plexus to the posterior roots of S2–S4. Some aspects
of micturition are centred in the pons, where detrusor contraction
is coordinated with inhibition of the distal sphincter. Interruption of
this pathway below the pons with preservation of the sacral cord is
likely to result in a contractile detrusor and tonically active distal
sphincter that will not relax during voiding (detrusor–sphincter
dyssynergia).
CONGENITAL DEFECTS OF THE BLADDER
Bladder exstrophy:
Bladder exstrophy occurs in 1:50 000 births (male–female ratio
4:1). In the male, the penis is broad and short, and bilateral
inguinal herniae may be present. There is separation of the pubic
bones In epispadias alone, the pubes are united and external
genitalia are almost normal, although in the female the clitoris is
bifid.
Treatment
The bladder is closed in the first year of life, usually following
osteotomy of both iliac bones just lateral to the sacroiliac
joints.Later, reconstruction of the bladder neck and sphincters is
required. In some patients the reconstructed bladder remains
small and requires augmentation. One-stage reconstruction is
being practised in some major centres. Less satisfactorily, urinary
diversion by means of ureterosigmoid anastomosis, an ileal or
colonic conduit,or continent urinary diversion. Long-term
complications include:
(1) stricture at the site of anastomosis with bilateral
hydronephrosis and infection;
(2) hyperchloraemic acidosis; and
(3) an increased (20-fold) risk of tumour formation (adenoma and
adenocarcinoma) at the site of a ureterocolic anastomosis.
BLADDER TRAUMA
Bladder rupture
1-Intraperitoneal rupture(20%) : is usually secondary to a blow or
fall on a distended bladder, more rarely to surgical damage.
Intraperitoneal rupture is associated with sudden severe pain in
the hypogastrium, often accompanied by syncope. The shock
subsides and the abdomen distends and there is no desire to
micturate. Peritonitis does not follow immediately if the urine is
sterile; varying degrees of rigidity are present on examination.
Investigation:
Computerised tomography (CT) is ideal. Plain erect radiographs
may show a ground-glass appearance (fluid). Intravenous
urography (IVU) may confirm a leak. Retrograde cystography will
confirm the diagnosis.It is important to image the patient after
drainage of contrast as the full bladder may mask extravasation.
Treatment of intraperitoneal rupture
A lower midline laparotomy should be performed; the edges of the
rent are trimmed and sutured with a single-layer 2/0 absorbable
suture. A suprapubic and a urethral catheter are placed.
Laparoscopic approaches are also now being used.
2- Extraperitoneal rupture(80%) is caused by blunt trauma or
surgical damage. Gross haematuria can be absent. It may be
difficult to distinguish extraperitoneal rupture from rupture of the
membranous urethra .
Injury to the bladder during operation
The bladder may be injured in: (1) inguinal or femoral herniotomy;
(2) hysterectomy; and (3) excision of the rectum. If the injury is
recognised, the bladder must be repaired and catheter drainage
maintained for 7 days. If it is not recognised, the treatment is
similar to that of rupture of the bladder.When accidental
extraperitoneal perforation of the bladder occurs during
endoscopic resection, drainage of the bladder with a urethral
catheter and antibiotics usually suffice. If a mass of extravasated
fluid is present it is best to place a small drain through a stab
incision. A laparotomy will usually be required if an intraperitoneal
perforation is caused by transurethral resection.
RETENTION OF URINE
Acute retention
The most frequent causes of acute retention
Male:
- Bladder outlet obstruction (the commonest cause)
-Urethral stricture
-Acute urethritis or prostatitis
-Phimosis
Female:
- Retroverted gravid uterus
- Bladder neck obstruction (rare)
Both:
- Blood clot
- Urethral calculus
- Rupture of the urethra
- Neurogenic (injury or disease of the spinal cord)
- Smooth muscle cell dysfunction associated with ageing
- Faecal impaction
- Anal pain (haemorrhoidectomy)
- Intensive postoperative analgesic treatment
- Some drugs antihistamines, anti-hypertensives, anticholinergics and tricyclic antidepressants.
- Spinal anaesthesia
Clinical features
No urine is passed for several hours. Pain is present.The bladder
is visible, palpable, tender and dull to percussion.
Potential neurological causes should be excluded by checking
reflexes in the lower limbs and perianal sensation.
TreatmentT:reatment is to pass a fine urethral catheter (14F –
French gauge is defined as the circumference in millimetres) and
arrange urological management. Occasionally, in postoperative
retention a
warm bath can help.
Urethral catheterisation
Hand wash, sterile gloves are donned. The genitalia are cleaned
using soapy antiseptic. Lignocaine gel is inserted into the urethra,
warning the patient that this may create stinging. The jelly should
be massaged posteriorly in an attempt to anaesthetise the
sphincter region. A small Foley catheter should be passed while
the penis is held taut. In a female patient, the labia should be
parted using the middle and index fingers of the left hand, which
should not be moved once cleaning has been performed. Once
urine begins to drain it is wise to pass a few more centimetres of
catheter into the bladder before the balloon is inflated to avoid
inflation in the prostate. Force must not be used If the catheter
will not pass, it is usually due to poor technique, lack of
anaesthesia, traumatisation of the urethra or a urethral
stricture.Occasionally, a large prostatic middle lobe may prevent
the catheter entering the bladder; sometimes a coudé catheter will
pass. If a catheter cannot be passed the following plan should be
pursued( Suprapubic) puncture
Suprapubic puncture: The skin, fascia and retropubic space are
anaesthetised with 0.5% lignocaine. Correct placement is
confirmed by aspiration. A large-bore needle is then placed into
the bladder, down which a fine catheter is passed (Cystofix) and
then secured in position. If these devices are not available, a
catheter can be placed in the bladder under direct vision through a
small incision under local anaesthetic. Urethral instrumentation In
a patient with a known stricture, an experienced urologist may
elect to dilate the stricture or to take the patient to theatre to
carry out an optical urethrotomy.
Chronic retention: no pain. with risk of upper tract dilatation
because of high intravesical tension – they require urgent
urological referral. Men with impaired renal function may develop
postobstructive diuresis following catheterisation. need careful
monitoring, with replacement of inappropriate urinary losses by
intravenous saline; also at risk of haematuria as the distended
urinary tract empties. The risk of ascending infection is decreased
by connecting the catheter to a collecting bag.
Retention with overflow
The patient is incontinent with small amounts of urine passing
involuntarily from the distended bladder. It usually follows a
neglected retention.