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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.