Urinary Tract / Kidney Stones
The urinary tract can be divided into three distinct, but not separate components; the kidneys, ureters, and the bladder. The kidneys produce urine, which is in turn delivered to the bladder via the ureters. Most of the stones that are produced within the urinary tract start off in the kidney and drop down to the bladder. Some stones never leave the kidney. For those that do drop out of the kidney, it is the trip to the bladder that causes most of the problems that patients encounter.
The Washington area is geographically within the northern most part of the stone belt. May through October seems to be the time of the year that we encounter the largest number of patients with stones, and has been dubbed stone season! While most of the stones that we encounter are calcium-based stones, there are also stones compose primarily of uric acid. Other less common stones, such as magnesium ammonium sulfate stones can be associated with chronic bacterial infections. Rarely, we may see patients with stones formed from cystine, protein matrix, and even certain pharmaceutical agents.
For the most part, kidney stones will pass spontaneously, without intervention. Unfortunately it is while they are passing, that patients will experience the pain that they will often never forget. This colicky type pain is often associated with nausea, vomiting, and a feeling of the need to either urinate constantly, or to move ones bowels. It is when the stones are either too large to pass, or the anatomy is altered in some way, so as to prevent the stone from passing, that the patient is advised to undergo some form of urologic intervention.
Kidney stones cause problems when they are of sufficient size so as to cause obstruction. If they are too large to pass into the ureter, they may not be painful, but may instead cause silent damage to the kidney. In the past, the only way to remove stones was to physically cut them out, via a large incision made in the patient's flank. During the mid 1980's we began to remove stones through small tubes inserted into the patient's kidney through the skin of the flank. This procedure, called the percutaneous nephrostolithotomy allowed us then, and now, to either remove, or to pulverize stones via a fiber optic telescope. The telescope and other required instruments are inserted through an incision no larger than 1 cm. At about this same time, the shock wave lithotripter was introduced, as a totally noninvasive means of pulverizing kidney stones. With the early Extracorporeal Shock Wave Lithotripters (ESWL) the patient was lowered into a large tub of water through which the shock waves were focused on the stone.
These powerful shock waves ideally cause the stone to break up into pieces less than 1mm. These pieces are subsequently passed down the ureter, and voided out during normal urination. The newer, more compact lithotripters, no longer require a tub of water, but use a water pillow instead, as a means of transmitting the shock waves to the stone. The recently published studies from the Mayo Clinic, which showed higher rates of both Diabetes and Hypertension after lithotripsy, were done using the older machines, which are not used at this time.
In some instances when we cannot see the stone well enough under fluoroscopy, in order to use the extra corporeal shock wave lithotripter, we will access the interior of the kidney, using a tiny fiber optic ureteroscope. This telescope is inserted into the patient's urethra, and passed retrograde up the ureter. A holmium laser fiber can then be inserted through the telescope. When placed directly on the stone, the laser can be used to break the stone into small passable fragments. In some instances the fragments will be removed with a small basket.
These same ureteroscopes can be used to access any part of the ureter between the kidney and the bladder. Small stones that do not pass on their own, can be removed in one piece via baskets inserted into the scope, or disintegrated using the holmium laser. In some instances, we can use the extra corporeal shock wave lithotripter to pulverize the ureteral stones. In an attempt to decrease the amount of pain that a patient encounters following any of these procedures, a small plastic tube known as a stent may be inserted into the ureter. This tube will allow the urine and some of the smaller fragments to pass through the otherwise swollen ureter. The stent will either be removed by pulling on a small string attached to its end, or via a cystoscope, under local anesthesia, at a later date. In many instances, we are able to leave this part of the procedure out. The amount of discomfort that may follow is variable. You can discuss all of the options for handling your stone, and possible stenting, with your doctor.
In cases when the patient presents with both a stone, and a temperature of over 101° F, an infection is usually present. In this instance, your physician may suggest that the stone not be removed until the infection has cleared. An infection "behind" an obstruction requires drainage. This will usually require that a stent be placed, followed by a definitive procedure, done at a later date. On rare occasions, stent placement is thought to be too risky, or difficult. We will then ask the interventional radiologist to place a percutaneous nephrostomy tube to drain the system. This will allow the infection to subside so that the stone can be handled with less risk of complications for the patient.
Complications as a result of procedures done to remove stones from the kidneys or the ureters are unusual but can happen under the best of circumstances. Post-operative bleeding, and pain, does not necessarily indicate a complication, as these are normal occurrences. Fever may indicate an infection. For this reason, most patients are given antibiotics following procedures involving the use of telescopes, with or without stenting. Rarely, damage to the ureter can occur. This unusual complication is most often treated with prolonged stenting, or placement of a nephrostomy tube. In the very unusual case of complete ureteral disruption, an open repair would be indicated.
When, indicated, following treatment of your stone, our physician will order studies to help determine the origin of the problem. In some instances, a referral to a nephrologist, with an interest in metabolic stone disease will be made.
Stones that grow to very large size in the bladder (>1cm) are usually associated with bladder outlet obstruction. This situation usually occurs in men and is secondary to prostatic enlargement. These stones can usually be broken up with the holmium laser, and removed through a fiber optic cystoscope. This procedure is often done in conjunction with a procedure to ease the outlet obstruction caused by the prostate. In rare occasions, the stone and the prostate are treated through a lower abdominal incision.
Each of our physicians has extensive experience with the evaluation and treatment of kidney stones. We have the most advanced technologies available to us, for use with our patients, at our hospitals and in some cases at the ambulatory surgery centers. If you are having problems with kidney stones, please call our office for an appointment. If you have had x-rays of any type taken in the days or weeks prior to your appointment, please bring them with you, so that we may review them at the time or your visit. Please call 202-223-1024 for an appointment with one of our physicians.