PERCUTANEOUS NEPHROLITHOTOMY RESULTS

percutaneous nephrolithotomy - diagnosis / preparation
Diagnosis : Kidney stones may be discovered during a routine x ray study of the patient’s abdomen. These stones, which would ordinarily pass through the urinary tract unnoticed, are sometimes referred to as silent stones. In most cases, however, the patient seeks medical help for sudden intense pain in the lower back, usually on the side of the affected kidney. The pain is caused by the movement of the stone in the urinary tract as it irritates the tissues or blocks the passage of urine.

If the stone moves further downward into the ureter (the tube that carries urine from the kidney to the bladder), pain may spread to the abdomen and groin area. The patient may also have nausea and vomiting, blood in the urine, pain on urination, or a need to urinate frequently. If the stone is associated with a UTI, the patient may also have chills and fever. The doctor will order both laboratory studies and imaging tests in order to rule out such other possible causes of the patient’s symptoms as appendicitis, pancreatitis, peptic ulcer, and dissecting aneurysm.

The imaging studies most commonly performed are x ray and ultrasound. Pure uric acid and cystine calculi, however, do not show up well on a standard x ray, so the doctor may also order an intravenous pyelogram, or IVP. In an IVP, the radiologist injects a radioactive contrast material into a vein in the patient’s arm, and records its passage through the urinary system in a series of x ray images. Blood and urine samples will be taken to test for indications of a urinary tract infection. If the patient passes the kidney stone, it is saved and sent to a laboratory for analysis.

percutaneous nephrolithotomy - preparation
Most hospitals require patients to have the following tests before a PCNL: a complete physical examination; complete blood count; an electrocardiogram (EKG); a comprehensive set of metabolic tests; a urine test; and tests that measure the speed of blood clotting. Aspirin and arthritis medications should be discontinued seven to 10 days before a PCNL because they thin the blood and affect clotting time. Some surgeons ask patients to take a laxative the day before surgery to minimize the risk of constipation during the first few days of recovery.

The patient is asked to drink only clear fluids (chicken or beef broth, clear fruit juices, or water) for 24 hours prior to surgery, with nothing by mouth after midnight before the procedure.
percutaneous nephrolithotomy - aftercare
A standard PCNL usually requires hospitalization for five to six days after the procedure. The urologist may order additional imaging studies to determine whether any fragments of stones are still present. These can be removed with a nephroscope if necessary. The nephrostomy tube is then removed and the incision covered with a bandage. The patient will be given instructions for changing the bandage at home.

The patient is given fluids intravenously for one to two days after surgery. Later, he or she is encouraged to drink large quantities of fluid in order to produce about 2 qt (1.2 l) of urine per day. Some blood in the urine is normal for several days after PCNL. Blood and urine samples may be taken for laboratory analysis of specific risk factors for calculus formation.

percutaneous nephrolithotomy - risks
There are a number of risks associated with PCNL:
• Inability to make a large enough track to insert the nephroscope. In this case, the procedure will be converted to open kidney surgery.
• Bleeding. Bleeding may result from injury to blood vessels within the kidney as well as from blood vessels in the area of the incision.
• Infection.
• Fever. Running a slight temperature (101.5°F; 38.5°C) is common for one or two days after the procedure. A high fever or a fever lasting longer than two days may indicate infection, however, and should be reported to the doctor at once.
• Fluid accumulation in the area around the incision. This complication usually results from irrigation of the affected area of the kidney during the procedure.
• Formation of an arteriovenous fistula. An arteriovenous fistula is a connection between an artery and a vein in which blood flows directly from the artery into the vein.
• Need for retreatment. In general, PCNL has a higher success rate of stone removal than extracorporeal shock wave lithotripsy (ESWL), which is described below. PCNL is considered particularly effective for removing stones larger than 1 in (0.5 cm); staghorn calculi; and stones that have remained in the body longer than four weeks. Retreatment is occasionally necessary, however, in cases involving very large stones.
• Injury to surrounding organs. In rare cases, PCNL has resulted in damage to the spleen, liver, lung, pancreas, or gallbladder.

Normal results
PCNL has a high rate of success for stone removal, over 98% for stones that remain in the kidney and 88% for stones that pass into the ureter.

Morbidity and mortality rates
Standard PCNL has a higher rate of complications than extracorporeal shock wave lithotripsy; however, it is more successful in removing calculi. The overall rate of complications following PCNL is reported as 5.6% in one recent study and 6.5% in a second article. About 20% of patients scheduled for PCNL require a blood transfusion during the procedure, with 2.8% needing treatment for bleeding after the procedure. The rate of fistula formation is about 2.5%.

Alternatives
Patients with kidney stones may be treated with one or more of the following procedures in addition to PCNL, depending on the size of their renal calculi and possible complications. One frequently used combination, known as sandwich therapy, is extracorporeal shock wave lithotripsy for smaller stones followed by PCNL to remove larger calculi.

Conservative approaches
Conservative forms of treatment include the following:
• Watchful waiting.
• Hydration. Increasing the patient’s fluid intake (to seven or more glasses of fluid each day) is a major component of treatment intended to prevent the formation of kidney stones. At least half of the fluid should be water.
• Dietary modification. Depending on the type of stone that has formed, the patient may benefit from eating less animal protein, avoiding vegetables with high oxalate content, cutting down on table salt and vitamin C intake, etc.
• Medications. Patients who tend to form uric acid stones may be given allopurinol, which decreases the formation of uric acid; those who form calcium oxalate stones may be given thiazide diuretics; and those who develop infection stones can be treated with oral antibiotics.

Open surgery
Open surgery is the most invasive form of treatment for urolithiasis. As of 2003, it is performed primarily to remove very large and complex staghorn calculi or extremely hard stones that cannot be broken down by lithotripsy. Other indications for open surgery are extreme obesity, an anatomically abnormal kidney, or an infected and nonfunctioning kidney requiring complete removal. Patients are usually hospitalized for a week after open kidney surgery and take about six weeks to recover at home.

Extracorporeal shock wave lithotripsy (ESWL)
ESWL is a noninvasive procedure that was developed in the 1980s as a less invasive alternative to PCNL. It is presently used more often than PCNL to treat smaller renal calculi. In ESWL, the patient is given a local anesthetic and placed in a water bath or on a soft cushion while shock waves are transmitted through the tissues of the back to the stones inside the kidney. The shock waves cause the calculi to break up into smaller pieces that can be passed easily in the urine.

Although patients need less time to recuperate from ESWL, it has several disadvantages. It has lower success rates (50–90%) than PCNL. Moreover, it cannot be used to treat cystine calculi or calculi larger than 1.2 in (3 cm). An additional concern with shock wave lithotripsy is its safety in treating small or anatomically abnormal kidneys; it has been reported to cause temporary damage to kidney tubules in smaller-than-average kidneys.

Ureteroscopy
Ureteroscopy refers to removal of calculi that have moved downward into the ureter with the help of a special instrument. A ureteroscope is a small fiberoptic endoscope that can be passed through the patient’s urethra and bladder into the ureter. The ureteroscope allows the surgeon to locate and remove stones in the lower urinary tract without the need for an incision.

Complementary and alternative (CAM) approaches
Vegetarian and other low-protein diets have been found helpful in preventing kidney stone formation. In addition, recent ethnobotanical studies of ammi visnaga (toothpick weed), a plant belonging to the parsley family, and Phyllanthus niruri, a traditional Brazilian folk remedy for kidney stones, indicate that extracts from these plants are effective in increasing urinary output and inhibiting the development of calcium oxalate calculi.