Generality
Lithotripsy still represents the first choice treatment of urolithiasis, a pathology better known as stones of the urinary tract.
Due to the precipitation or aggregation of solutes present in the urine, crystalline aggregations called calculi can develop in the different parts of the urinary tract: kidneys, ureters, bladder and urethra. These concretions, comparable to small pebbles, can be disintegrated from sources energy of various kinds, such as sound waves or laser rays: this is precisely the principle of lithotripsy, a technique that allows the shattering of the stone facilitating its spontaneous expulsion through the urine or forced by endoscopic instruments inserted into the patient's body.
The lithotripsy techniques are essentially divided into:
1) Extracorporeal lithotripsy: treatment carried out without anesthesia; it allows the crushing of the stone using a device external to the patient; this machine, called lithotripter, is able to produce a beam of "shock waves" that breaks on the solid surface of the stones, identified by fluoroscopy or ultrasound;
2) Intracorporeal lithotripsy: endoscopic surgery that allows the crushing of the stone using a device that generates shock waves at a close distance from the stone, therefore directly inside the patient. Intracorporeal litrotrissia is in turn divided into:
I) percutaneous nephrolithotripsy: access to the stone occurs through a hole made in the lumbar area, through which an endoscope is slid to reach the kidney and locate the stone, then the probe capable of emitting the energy intended to shatter it.
II) ureterolithotripsy (endoscopic ureteral lithotripsy): access to the stone occurs through the urethra, the channel that conveys the urine accumulated in the bladder to the outside; from here the urethroscope reaches the bladder and is then inserted into the ureter;
The fragments of the stone generated by intracorporeal lithotripsy can be recovered using special forceps or baskets.
Extracorporeal lithotripsy
The choice of adopting one type of lithotripsy rather than another depends on the location, size and composition of the stone.
Extracorporeal lithotripsy is certainly less invasive and better tolerated by the patient: it is performed on an outpatient basis and in most cases is almost painless, so much so that at most a slight pharmacological sedation is required. Unfortunately, however, its application is reserved for cases in which the stone has a sufficiently small diameter (less than 2 cm), a favorable localization (urethral stones, stones located in the renal pelvis or in the upper calyxes) and a not excessive hardness ( indicated in the presence of calcium-oxalate, struvite, cystine and brushite stones; generally ineffective in case of cystine and calcium oxalate monohydrate stones). Outside of these series, extracorporeal lithotripsy could not only be ineffective, but even potentially dangerous for the patient. The stone fragments generated by the surgery, in fact, must be eliminated in the urine, with the risk - if too large - of causing colic, acute urinary retention, infections and tissue damage.
EXTRACORPOREAL LITHOTRISSIA CHARACTERISTICS OF THE CALCULATIONS % SUCCESS Size <1 cm 84% (64-92%) Size> 1cm <2cm 77% (59-89%) Dimensions> 2 cm 63% (39-70%) Dimensions> 2.5 Poor Location Renal pelvis 80% * Localization of the upper chalices 73% * Location Lower calyx 53% * * These percentages clearly decrease in case of stenosis of the collar of the calyxes: 26 and 18% respectively for upper and lower calicial stones.
The fragments produced by lithotripsy are eliminated in most cases (55 to 78% one year after treatment).
POST-INTERVENTION COMPLICATIONS INCIDENCE Renal colic due to the expulsion of stone fragments 18,4 - 49%. Renal hematoma 0,1 - 0,6%. The shock waves produced by the lithotripter external to the patient propagate through the tissues with low attenuation, generating minimal but not negligible damage. This is why they represent absolute contraindications to the intervention: skeletal malformations, aneurysms of the aorta and renal artery, obesity , pregnancy and uncorrectable bleeding disorders. Before extracorporeal lithotripsy it is also necessary to evaluate the state of health of the heart and the coagulation capacity of the blood; any drugs that alter platelet aggregation (Aspirin) or coagulation (Coumadin) will be suspended in time according to medical indications.
To facilitate the expulsion of the stone after lithotripsy, the so-called hydropinic therapy with minimally mineralized water can be useful to be taken in generous quantities (3/4 liters / day) according to medical indications. In this phase, the administration of herbal extracts may also be useful. diuretic action, while it is good to have at hand a painkiller (diclofenac or similar) and a bag of hot water to deal with any renal colic in the bud. In the post-surgery episodes of hematuria (blood in the urine) and mild kidney pain if the shock waves were directed at kidney stones; if more serious symptoms appear, such as fever and chills, call emergency services immediately.
After extracorporeal lithotripsy it is necessary to undergo regular ultrasound checks to evaluate the outcome of the operation and prevent possible recrudescences. If the operation has not been able to free the kidney from the stone, the doctor may suggest the repetition of the lithotripsy for one, two, three or more times.
Intracorporeal lithotripsy
Intracorporeal lithotripsy is performed in all those cases in which the extracorporeal technique is not practicable; considering the invasiveness of the procedure, however inferior to the traditional surgical technique, the operation is performed under general anesthesia and involves hospitalization for a few days. This requires greater investigations in the preparatory phase for surgery, and exposes the patient to a higher risk of complications during lithotripsy, such as renal haemorrhage in the case of percutaneous lithotripsy or rupture of the ureter in the case of ureterolithotripsy.
