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TUR - PROSTATE

MH KAMAT

Consultant Urologist, Jaslok Hospital and PD Hinduja National Hospital, Mumbai.
INTRODUCTION

The success of any surgical procedure depends not only on technique of surgery but also on careful attention to the following factors :

i) Selection of patient with clear and appropriate indication for surgery.
ii) Pre-operative assessment and treatment of patho-physiological changes that may be present as a result of the disease and may affect the outcome of surgery.
iii) Pre-operative assessment and treatment of co-morbidities affecting risk of surgery.
iv) Careful attention to surgical technique including full awareness of possible complications and steps necessary to avoid them.

Let us consider all these one by one.

INDICATIONS FOR SURGERY IN ENLARGED PROSTATE


In earlier days, symptoms of prostatism were indications for surgery. Now the indications for surgery are :

i)Refractory urinary retention
ii)Recurrent UTI
iii)Large bladder diverticulum
iv)Recurrent gross haematuria to BPH
v)Bladder stone due to BPH
vi)Renal impairment due to BPH
vii)Failure of medical treatment

A patient with enlarged prostate may present with :

Obstructive symptoms (hesitancy, thin stream, interrupted flow, straining to void and sense of incomplete voiding) respond well to TUR-P.

Symptoms of detrusor irritability (frequency, urgency and urge-incontinence) may improve in course of time after TUR-P if the irritability is secondary to obstruction.

Some patients have primary detrusor instability (uninhibited bladder contractions) and require treatment with anti-cholinergic drugs even after TUR-P. The advantage of TUR-P in these cases is that the required dosage of anti-cholinergic drugs can be used without fear of retention.

Pre-operative Assessment and Treatment of Patho-physiological Changes that may be Present as a Result of the Disease and may Affect the Outcome of Surgery

Hypotonic or atonic bladder due to longstanding obstruction and large residual urine is not uncommon. With adequate drainage over a period of time, most of these bladders regain adequate tone and function. Assessment with cystometry is essential and TUR-P should be done after the detrusor function is regained.

Large diverticulum must be excised along with removal of prostate. A diverticulum does not have muscle wall and if it is not removed, patient will continue to have residual urine, infection etc. even after TUR-P.

Obstructive uropathy with impaired renal function : Increases the risk of surgery.

Severe urinary infection must be controlled be fore surgery.

Other pathologies that are not uncommonly associated and may affect the outcome are

Small prostate with prostatitis and/or fibrous prostate : The incidence of bladder neck stenosis after TUR-P is higher in these cases. TUI-P with, if necessary, limited resection of posterior ridge, is preferable.

Prostate abscess : delay in healing and persistent bacteriuria after TUR-P can occur.

Associated urethral stricture : obstructive symptoms recur because of re-stenosis of stricture and are wrongly attributed to failure of TUR-P.

Diabetes and Parkinsonism : Neurological effects on bladder may affect the final outcome.

Pre-operative assessment and treatment of co-morbidities affecting risk of surgery

The common diseases encountered in these old patients are : Diabetes, ischemic heart disease, hypertension.

Other common problems are : Anti-coagulants / haematologic problems / G6-PD-deficient / electrolytes imbalance due to use of diuretics etc.

Careful attention to surgical technique including awareness of possible complications and steps necessary to avoid them

Pre-op : Proper and adequate antibacterial coverage. This is particularly important in patients with urinary infection to prevent septicaemia, because bacteraemia can take place during resection of prostate.

Assessment of electrolytes and correction of imbalance : Hypertensive patients who are on diuretics may have low serum sodium and this may contribute to TUR-P syndrome.

Resectoscope: "Continuous Irrigating Resectoscope" is essential. It reduces the time of resection and minimizes the absorption of irrigation fluid by keeping the vesical pressure low. The 30 degree macrolense telescope must be in good condition.

Electro-surgical Unit : I cannot emphasize enough the necessity of a good electro-surgical unit, the one that provides precise cutting and coagulation without charring the tissue.

Video : Use of video during resection has many advantages. It gives magnification and without awkward movements of neck, operator can visualize all areas of prostate. Changing from direct vision to use of video is not difficult.

Anaesthesia : Spinal or epidural is preferred. It has many advantages such as : no bladder spasms during resection, patient being fully awake any signs of hypervolaemia can be detected early, anaesthetic effect lasts even after completion of surgery and gradually wears off avoiding bladder spasms and pain in the immediate post-operative period.

Irrigating solution : The two commonly used are water and glycine. Though glycine is commonly used, I prefer sterile water, except in large adenomas with renal impairment.

Water gives clear view but has the disadvantage that its extreme hypotonicity causes haemolysis. If absorbed in larger quantities, haemolysis will cause renal impairment.

Many urologists are not fully aware of the problems glycine can cause. 1.5% glycine used for irrigation is not isotonic, its osmolality is 230 mosm/l compared to serum osmolality of 290 mosm/l and hence some haemolysis can occur after its absorption. 2.2% glycine is isotonic but at this concentration it is highly toxic.

Glycine is toxic to heart and retina, causing visual disturbances and increasing the long-term risk of myocardial infarction. It is a major inhibitory neurotransmitter in the spinal cord and brain stem, probably acting in the same manner as gamma amino butyric acid on the chloride ion channel. High concentration causes depressant effect on the CNS.

Ammonia is a major by-product of glycine metabolism. High ammonia concentration suppresses dopamine and norepinephrine release in the brain, causing encephalopathy. Fortunately, ammonia toxicity is rare.

Actual technique : Urethroscopy and careful cystoscopy examination is done. If urethra cannot easily accommodate the resectoscope, I prefer urethral dilatation to urethrotomy.

Resection should start at the floor of the bladder neck, taking care not to cut the trigone. In large median lobe, there is a danger of resecting the trigone. The resection of lateral lobes is done in a concentric fashion. This means cutting a little bit all around till a passage is obtained from the verumontanum to the bladder cavity. This allows easy flow of irritating fluid in the bladder when deeper resection of the lobes is undertaken, thus minimizing the absorption of irrigation fluid. As the concentric resection proceeds, deeper parts of adenoma are resected till the fibres of the surgical capsule are exposed.

Resection of the distal adenoma is done last. Before undertaking this, the haemostasis should be good so that the vision is not impaired. Distal adenoma is resected with "scooping" movements of the resecting loop. This avoids cuts from extending beyond the verumontanum. Complete coagulation is obtained at the end.

Post-operative : 22-Fr three-way Foley is left indwelling at the end of resection. Gentle traction is applied to the catheter. Bladder irrigations are continued for 24 hours. The catheter is usually removed after 48 hrs. Antibacterial coverage is continued at least for a week after removal of the catheter and thereafter only if the urine shows infection.

The two important complications of TUR-P surgery that need attention are :

Intra-operative Bleeding

With clear wide-angle macro-lenses and further magnification obtained by the use of video, arterial bleeding can be easily identified and coagulated. Therefore, with good equipment, the blood loss during TUR-P is minimal.

If you do not see any bleeder and yet the drainage is bloody, there are two possibilities : i) Venous sinus bleeding which stops temporarily due to the flow of irrigation fluid and hence not seen when looked at. Bleeding from venous sinus cannot be stopped by coagulation. It will subside after the Foley catheter has been inserted. ii) Arterial bleeder pumping into bladder cavity and not seen while inspecting the resected prostate cavity. Careful look at the vesical side of bladder-neck will reveal it.

TUR-P syndrome

This is a syndrome that results from absorption of irrigation fluid causing i) circulatory overload and ii) dilutional hyponatraemia.

The main factor that contributes to this is increased absorption of irrigation fluid during resection. This can be minimized by the following measures : i) keeping the irrigation can less than two feet above the level of bladder, ii) avoiding opening of venous sinus, iii) limiting the time of resection to less than one hour.

Glycine or water will have the same effect on circulatory overload. However, larger amount of glycine stimulates the release of atrial natriuretic peptide in excess of that expected by the volume load. This promotes natriuresis and further aggravates hyponatraemia.

Since patient is awake under spinal anaesthesia and is being monitored during surgery with ECG monitor and pulse oxymeter, the following points should be remembered :

The symptoms of hyponatraemia are : restlessness, confusion, incoherence, coma and seizures. The serum sodium fall effects are :

< 120 meq/l : hypotension and reduced myocardial contractility.

< 115 meq/l : bradycardia and widening of QRS complexes, ventricular ectopics and T wave inversion

< 100 meq/l : generalized seizures, coma, respiratory arrest, ventricular tachycardia, ventricular fibrillation and cardiac arrest.

With proper precautions and attention to technical details outlined above, TUR-P syndrome can be avoided.

The overall results of TUR-P in properly selected cases are excellent. Patient is unhappy only when the symptoms of bladder instability viz. frequency, urgency continue even after TUR-P. As explained above, in some elderly patients these are due to "primary bladder instability" and require the use of anti-cholinergic drugs. The patients in whom the obstruction and primary bladder instability co-exist, TUR-P allows us to use these drugs without the fear of retention. The urodynamic study cannot distinguish between primary bladder instability and that which is secondary to bladder outlet obstruction.


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