Surgical anatomy
- Prostate is a male sex organ, surrounding the beginning of male urethra and consists of glandular tissue in a fibromuscular stroma.
- Its base is directed upwards to bladder neck, its apex directed down wards and resting on external sphincter, its posterior surface is palpable through rectum.
- There are right and left lateral lobes, attach anteriorly by anterior lobe and separated posteriorly by a median furrow, which itself is divided by the ejaculatory ducts into an upper middle lobe and a lower posterior lobe.
- There are two kinds of glands one in inner zone, submucosal glands (adenomatous zone) which surrounds the urethra and other are in outer zone, prostatic glands proper (carcinomatous zone).
- Prostate has its own thick fibrous capsule and outer to it prostatic plexus of veins are in loose pelvic fascia.
- Smooth muscle cells are found throughout the prostate but in the upper part of the prostate and the bladder neck, there is a separate sphincter muscle that sub serves a sexual function, closing during ejaculation, resection of this tissue during prostatectomy is responsible for retrograde ejaculation.
- The distal striated urethral sphincter muscle is found at the junction of the prostate and the membranous urethra; it is horse shoe shaped with the bulk lying anteriorly and is quite distinct from the muscle of the pelvic floor, its damage leads to incontinence.
- The neurovascular bundles supplying autonomic innervations to the corpora of the penis are in very close relationship to the postero lateral aspect of the prostatic capsule and are at risk of damage during radical prostatectomy or inadvertent diathermy in this region during transurethral prostatectomy, leading to impotence.
- Blood supply is from the internal iliac artery and venous drainage into the plexus around the gland and then into the internal iliac veins.
- Lymph drainage to internal iliac lymph nodes.
Benign Prostatic Hypertrophy
- Benign hypertrophy (BPH) is an old age problem (5th decades onwards) and common cause of prostatism in men > 70 years of age.
- Caused by changes in hormonal activity with increasing age, as serum testosterone levels slowly but significantly decrease with advancing age; however, levels of oestrogenic steroids are not decrease equally, so the prostate enlarge because of increased oestrogenic effects.
- Benign hypertrophy (BPH), or hyperplasia affects the glandular elements and connective tissue (usually in inner zone glands), but in variable degrees, forming a nodular enlargement which compresses the external glands into a false capsule.
- Any part of prostate may be involved, but usually it is the lateral lobes and meddle lobe.
- Lateral lobes enlargement obstructs the outflow of urine by narrowing, distorting and elongating the urethra.
- Middle lobe enlargement bulges into the bladder and can obstruct the outflow of bladder neck by ball valve mechanism on contraction of bladder.
- Sometime, both lateral lobes also project into the bladder, so that, when viewed from within, the sides and back of the internal urinary meatus are surrounded by an intravesical prostatic collar.
- The bladder responds to obstruction by hypertrophy (trabeculation, sacculation, diverticula formation), or atony (the bladder decompensate so that detrusor contraction becomes progressive less efficient and a residual urine develops).
- Kidneys respond to obstruction and vesicoureteric reflex by hydroureter, hydronephrosis, ascending infection – pyelonephritis and chronic renal failure.
Clinical Features
- Lower urinary tract symptoms can be described as:
- Voiding
Hesitancy (worsened if the bladder is very full);
Poor flow (unimproved by straining);
Intermittent stream- (stops and starts);
Dribbling (including after micturition);
Sensation of poor bladder emptying;
Episodes of near retention. - Storage:
Frequency is the earliest symptom especially nocturnal.;
Nocturia;
Urgency;
Urge incontinence;
Nocturnal incontinence (enuresis) - Others:
Pain due to cystitis or acute retention.
Chronic retention.
Retention with overflow
Haematuria due to congested veins (vesicle piles)
Urinary infection and stone formation
Renal insufficiency at end. - History:
Symptom score sheets such as the International Prostate Symptom Score (IPSS) assign a score which gives information regarding the severity of symptoms at the outset and changes over time and following intervention.
Examinations
- General physical examination may demonstrate signs of chronic renal impairment, anemia, dehydration.
- Abdominal examination- distended bladder is palpable in chronic retention.
- Rectal examination:-In benign enlargement, the prostate is enlarge its posterior surface is smooth, convex and typically elastic, but the fibrous element may give the prostate a firm consistency. The rectal mucosa can be made to move over the prostate.
- The external urinary meatus should be examined to exclude stenosis and the epididymides are palpated for sign of inflammation.
- The nervous system:- It is examined to eliminate a neurological lesion. Examination of perineal sensation and anal tone is useful in detection of an S2 to S4 cauda equina lesion. Diabetes mellitus, tabes dorsalis, disseminated sclerosis, cervical spondylosis, Parkinson’s disease and other neurological states may mimic prostate obstruction. If these are suspected then a pressure-flow urodynamic study should be carried out to diagnose BOO (Urinary flow rate and residual volume measurement)