PERCUTANEOUS NEPHROLITHOTOMY PCNL
Category: Urology
Abstract :
percutaneous nephrolithotomy Definition : Percutaneous nephrolithotomy, or PCNL, is a procedure for removing medium-sized or larger renal calculi (kidney stones) from the patient’s urinary tract by means of an nephroscope passed into the kidney through a track created in the patient’s back. PCNL was first performed in Sweden in 1973 as a less invasive alternative to open surge
percutaneous nephrolithotomy
Definition : Percutaneous nephrolithotomy, or PCNL, is a procedure for removing medium-sized or larger renal calculi (kidney stones) from the patient’s urinary tract by means of an nephroscope passed into the kidney through a track created in the patient’s back. PCNL was first performed in Sweden in 1973 as a less invasive alternative to open surgery on the kidneys.
The term percutaneous means that the procedure is done through the skin. Nephrolithotomy is a term formed from two Greek words that mean kidney and removing stones by cutting.
Purpose
The purpose of PCNL is the removal of renal calculi in order to relieve pain, bleeding into or obstruction of the urinary tract, and/or urinary tract infections resulting from blockages. Kidney stones range in size from microscopic groups of crystals to objects as large as golf balls. Most calculi, however, pass through the urinary tract without causing problems.
Renal calculi are formed when the urine becomes supersaturated (overloaded) with mineral compounds that can form stones. This supersaturation may occur because the patient has low urinary output, is excreting too much salt, or has very acid urine. Urolithiasis is the medical term for the formation of kidney stones; the word is also sometimes used to refer to disease conditions associated with kidney stones.
There are several different types of kidney stones, in terms of chemical composition:
• Calcium oxalate calculi.
About 80% of calculi found in patients in the United States are formed from calcium combined with oxalate, which is a salt formed from oxalic acid. Some foods, such as rhubarb and spinach, are high in oxalic acid. Oxalic acid is also formed in the body when vitamin C is broken down. Oxalic acid is ordinarily excreted through the urine but may be absorbed in large amounts due to chronic pancreatic disease or surgery involving the small intestine.
• Uric acid calculi.
These stones develop from crystals of uric acid that form in highly acidic urine. Uric acid calculi account for about 5% of kidney stones. In addition, some kidney stones are a combination of calcium oxalate and uric acid crystals.
• Cystine calculi.
Cystine calculi represent about 2% of kidney stones. Cystine is an amino acid found in proteins that may form hexagonal crystals in the urine when it is excreted in excessive amounts. Kidney stones made of cystine indicate that the patient has cystinuria, a hereditary condition in which the kidneys do not reabsorb this amino acid.
• Struvite calculi.
Struvite is a hard crystalline form of magnesium aluminum phosphate. Kidney stones made of this substance are formed in patients with urinary tract infections caused by certain types of bacteria. Struvite calculi are also known as infection calculi for this reason.
• Staghorn calculi.
Staghorn calculi are large branched calculi composed of struvite. They are often discussed separately because their size and shape complicate their removal from the urinary tract.
Some people are more likely than others to develop renal calculi. Risk factors for kidney stones include:
• Male sex.
• Family history. Having a first-degree relative with urolithiasis increases a person’s risk of developing kidney stones.
• Age over 30.
• Diet. People whose diet is high in protein or who eat foods rich in oxalate are more likely to develop kidney stones.
• Dehydration. People who do not drink enough fluid each day to replace what is lost through perspiration and excretion produce very concentrated urine. It is easier for crystals to form in concentrated than in dilute urine, and to grow into kidney stones.
• Metabolic disorders affecting the body’s excretion of salt or its absorption of calcium or oxalate. Most cases of urolithiasis in children are related to metabolic disorders.
• Intestinal bypass surgery and ostomies. People who have had these surgical procedures lose larger than average amounts of water from the digestive tract.
Demographics
Calculi in the urinary tract are common in the general United States population. Between seven and 10 in every 1,000 adults are hospitalized each year for treatment of urolithiasis; in addition, kidney stones are found in about 1% of bodies at autopsy. An estimated 10% of the population will suffer from kidney stones at some point in life. For reasons that are not yet known, the percentage of people with kidney stones has been rising in North America since 1980. In addition, the gender ratio is changing as more women are developing kidney stones. In 1980, the male:female ratio was 4:1; as of 2002, it was 3:1. Although more men develop renal calculi in general than women, more women develop infection calculi than men.
In terms of age groups, most people with urolithiasis are between the ages of 20 and 40; kidney stones are rare in children. A person who develops one kidney stone has a 50% chance of developing another. With regard to race, Caucasians are more likely to develop kidney stones than African Americans.
Description
Standard PCNL
A standard percutaneous nephrolithotomy is performed under general anesthesia and usually takes about three to four hours to complete. After the patient has been anesthetized, the surgeon makes a small incision, about 0.5 in (1.3 cm) in length in the patient’s back on the side overlying the affected kidney. The surgeon then creates a track from the skin surface into the kidney and enlarges the track using a series of Teflon dilators or bougies. A sheath is passed over the last dilator to hold the track open.
After the track has been enlarged, the surgeon inserts a nephroscope, which is an instrument with a fiberoptic light source and two additional channels for viewing the inside of the kidney and irrigating (washing out) the area. The surgeon may use a device with a basket on the end to grasp and remove smaller kidney stones directly. Larger stones are broken up with an ultrasonic or electrohydraulic probe, or a holmium laser lithotriptor. The holmium laser has the advantage of being usable on all types of calculi.
A catheter is placed to drain the urinary system through the bladder and a nephrostomy tube is placed in the incision in the back to carry fluid from the kidney into a drainage bag. The catheter is removed after 24 hours. The nephrostomy tube is usually removed while the patient is still in the hospital but may be left in after the patient is discharged.
Mini-percutaneous nephrolithotomy
A newer form of PCNL is called mini-percutaneous nephrolithotomy (MPCNL) because it is performed with a miniaturized nephroscope. MPCNL has been found to be 99% effective in removing calculi between 0.4 and 1 in (1 and 2.5 cm) in size. Although it cannot be used for larger kidney stones, MPCNL has the advantage of fewer complications, a shorter operating time (about one and a half hours), and a shorter recovery time for the patient.
Hit: 285 times
Related Articles in Urology :
|
Add to My Bookmarks
Make My Homepage
Print
Send to a friend
Advertise with Us