Prevention of Stone Disease
Most patients will have a further stone episode within 10 years. After the stone has been analyzed and the patient is asymptomatic, and provided that no other significant risk factors have been identified, most patients are advised regarding adequate fluid intake and dietary moderation. Reduced salt and red meat intake as well as taking at least 4oz of lemon juice (made into lemonade) each day has been shown to decrease calcium oxalate stone recurrence. Fluid intake is usually adequate once the urine is almost as clear as the water they drink. Further metabolic evaluation is usually not undertaken until the patient has had more than two stone episodes. Patients with uric acid stones need to moderate foods with high purine content such as shellfish and lobster and also maintain a liberal fluid intake.
Treatment of Symptomatic Stones
A conservative trial can be followed in those whose pain is controlled and have no septic episodes and in those that have two functioning kidneys. Most patients present with a stone in the end of the ureter, and at least 50% of these will pass spontaneously.
i. Ureteroscopic stone extraction.
Patients who have a stone in the lower ureter and who fail a trial of conservative care can benefit from outpatient laser ureteroscopic stone extraction. As an outpatient under a general anesthetic, a specialized telescope is advanced up the affected ureter and a laser probe used to break the stone. A flexible ureteroscope may be used to visualize stones in the kidney. Fragments can then be removed with a special wire basket and a double-J stent left in place in the ureter that can be removed in the office a day or two later. This stent allows urine to pass from the kidney to the bladder; otherwise, swelling of the ureter from the instrumentation would obstruct the ureter and cause intense pain.
ii. Extracorporeal shock wave lithotripsy (ESWL).
Renal and some ureteral stones can be fragmented through a process whereby shock waves are delivered through the body onto the stone using x-ray control. This applies usually only to stones that can be seen under x-rays. Stents may or may not be used. The stone fragments will usually pass within a 2-week period.
iii. Percutaneous nephrolithotomy.
Needle puncture of the kidney under a general anesthetic, subsequent tract dilatation and use of a specialized rigid or flexible nephroscope with or without the use of laser fibers may allow direct visualization and destruction of renal calculi. Remaining calculi may be retrieved through various alternative and additional procedures if dealing with complicated kidney anatomy and very large stones. For example, additional percutaneous puncture access, ESWL, flexible ureteroscopes and/or irrigations through the nephrostomy tract may be reasonable.
iv. Open Surgery Procedures for Stones.
Because of the foregoing, it is very unusual to have to resort to any of the open procedures that were at one time standard approaches to those with stone disease.