List Last 25 FAQs

You might not be able to avoid statistics. But sometimes authors show some other useful numbers you should look for. Let’s imagine 1000 people driving on the highway. In a construction area, suppose there are twenty accidents a day for those thousand people. In the non-construction area let there be five accidents. Let’s say the mileage of each stretch is the same so we have no “bias”.

1.  Relative risk: 20 accidents without construction and 5 with it. The risk of accident in the construction area is 20/1000 (2%). The risk of accident in the normal area is 5/1000 (0.5%). The relative risk is 20/5, or 2%/0.05% which equals 4. You are four times more likely to have an accident in the construction area.

2.  Absolute risk: If there is a 2% chance of accident in the construction area, and 0.5% risk otherwise, then the absolute difference is 2 – 0.5 = 1.5% and you could say that driving in the construction area raises your risk of accident by 1.5%. This doesn’t sound as bad as relative risk. It probably is the better way of looking at it, and isn’t as dramatic.

What if putting a cool new sensor in your car lowered your chance of accident in the construction area by 20%, so the numbers of accidents in construction are now 16 and in the clear are 5. This is like getting a treatment for a disease.

3.  Relative risk reduction: the new relative risk is 16/5 = 3.2, and the relative risk has lowered from (4-3.2)/4 = 20%. It isn’t a surprise that the number is 20%. We already said that the sensor made one group 20% better, a relative improvement.

4.  Absolute risk reduction: first find the absolute risk for the situation with the sensor, and it is (16-5)/1000 = 1.1%, so the absolute reduction is 1.5 – 1.1 = 0.4% and this is how much the sensor lowers accidents overall.

5.  Number needed to treat: this is the number of sensors we would have to install to prevent one accident. This is one of my favorite numbers because if the number is really high, then maybe it isn’t worth giving a medicine or treatment to all those patients. In our situation, we find that the number of sensors that have to be installed to prevent one accident among 1000 drivers is 1/(absolute risk reduction) = 25. Might be worth it? Only if you are one of the ones that was going to have an accident, and we don’t know that ahead of time do we? Such is statistics. Nobody can predict the future for an individual, but we can get an idea of what will happen to the herd.

Most good papers have a table that shows how the cohorts or groups are alike in a number of areas. This allows the reader to see just how different they might be when compared to ask the question about how their differences matter. It also can show areas of bias that change the answer because some treatment or disease outcomes can be changed by the selection of a subtly different cohort. 

Statistical data is collected and put on a graph, even if the graph isn’t in the paper. When data is plotted with trial subjects it usually follows a “bell curve”, with most of the people getting one result, and as you move away from the middle, fewer and fewer people get more or less of a result. In other words, most people driving on the interstate are going 75. Fewer are going 70 or 80. Even fewer are going 65 and 80 and so on. It is rare for someone to go 100, and also rare for 40 (unless on the ramp!). The people going at 40 or 100 are on the “tails” of the curve. The majority going 65-80 are in the fat bell-shaped middle. 

If the question being studied really makes a difference, then the bell curve will move for the group getting that difference. How much movement is reflected by a value called the “p-value”, which gets very small when the difference is higher. If the difference is very low, then the item studied doesn’t matter much, and the p-value is high. Most people think that a p-value <0.05 makes the result "significant" or not due to a random event. This isn't always so but it is a good rule of thumb. Look for "confidence intervals" which aren't as black/white as a low p-value. These are very good because they average the statistical results and give a range of probable truths. You might see this as saying that drug A worked for 10% (95% CI -8 - +20). This means that it worked about 10% of the time, but to get 95% confidence it could be as low as -8% (they got worse!) to +20% (even better). Drug A might not be so hot. On the other hand, if it is drug B worked 65% (95% CI +62 - +80) then there is going to be a lot of people wanting that item! The bigger the trial, the smaller the spread of CI values. Note that this is a 95% CI - the tails are left out because those values are happening to the fewest numbers of people. The statistics will talk about the one-tailed or two-tailed test. If something can go up OR down, then a two-tailed test is needed because the people at the top AND the bottom of the curve can be moved around. They will also talk about paired tests. In general if you measure something once, and then measure it again later, you need a paired test because the results are probably related to each other. A good example is pulse rate; the guy with a pulse of 50 at the beginning will likely have a lower pulse later than the guy that starts at 90 - the data is paired. Sometimes the statistics seek to say that something caused something else, and a lot of information about correlation will be presented. An example of this is using statistics to say that drunk driving causes accidents, or "correlates" with them. An "r-value" will be presented but this isn't always used correctly. Be skeptical. Decide if it makes sense that it correlates. Look for other things to explain the finding.

Everyone is a little different about how they feel when a procedure like cystoscopy is done in the office. Hundreds of these procedures are done in our city weekly, and very few patients experience anything more than mild discomfort as a result. The cystoscope is a flexible camera system the size of a normal urinary catheter. It is connected to a lens system that allows the urologist to inspect the urethra and bladder. Each urologist may vary their technique a bit, but this system was adopted by most urologists so that this common procedure could be done in the office without much difficulty. If your condition is complex or there is a reason that immediate treatment of a problem would be needed, the cystoscopy would be done in the operating room with anesthesia. But for simple observation and diagnosis that isn’t needed.

Scrotal varicoceles occur when the veins that drain a testicle are enlarged. There are four grades of varicocele. Subclinical grade is a varicocele which is detectable with ultrasound. Grade 1 is detectable by touch only with valsalva, as when coughing or bearing down. Grade 2 is detectable by touch without valsalva, as when lying down or at rest. Grade 3 can be seen with the eye, and obvious without feeling them. They are more common on the left, since the left spermatic vein drains to the left renal vein which has more pressure than where the right drains; the inferior vena cava. Varicoceles can affect fertility by lowering sperm count and motlity. Rarely varicoceles can occur due to masses in the abdomen or vascular problems. Other than that, they are benign and wouldn’t require treatment unless fertility is an issue or they are bothersome in some way.

Testicular torsion is one of the emergencies encountered in Urology. With testicular torsion the cord bringing blood to and from the testicle is twisted, the blood supply to the testicle is interrupted and it will eventually die. How long that takes depends on the circumstances and the person, but most urologists consider four hours the maximum time of torsion to prevent injury. The more time torsed, the more injury will be incurred. A torsed testicle is usually very tender, and doesn’t retract normally with cremasteric muscle stimulus. It usually swells as well. Some people have intermittent torsion – the testicle rotates into a problematic position, but can be returned to normal anatomic position without treatment. If you suspect torsion, go to the emergency room for evaluation. If you have intermittent pain but no lasting torsion, make an appointment to be seen by your urologist for evaluation – sometimes surgery is done to ensure the testicle cannot torse. The opposite testicle is usually fixed in place when a surgery is done to prevent a torsion on the other side.

That depends on where they are. In the female vagina, the conditions are usually such that the sperm live for 4 to 5 days, so that fertilization can occur. Outside of that, they can only live for a few minutes or an hour, depending on moisture and other variables. Millions of sperm are ejaculated with each climax, so the number of sperm still living will dwindle with time until eventually they all die.

There is always sperm in the vas deferens, the tube that carries sperm from the testicles to the prostate where it is mixed with the rest of seminal fluid. During ejaculation the vas deferens undergoes rhythmic contractions that propel sperm forward. This occurs during orgasm no matter whether it is with masturbation or during intercourse. If sperm isn’t ejaculated for a long time, as would happen if a person were completely sexually inactive; or if a vasectomy were done to divide the vas deferens, they eventually die and are reabsorbed by the body, with no effect at all.

Priapism is one of the emergencies of urology. It is a prolonged erection, of such duration that reduction of bloodflow to the tissues of the penis can cause oxygen starvation and permanent injury. Most urologists consider four hours too long to maintain an erection without injury. It can be painful, but isn’t always. Priapus was a Greek mythological figure and you can read more about it at Wikipedia. It can be caused by medications (Trazodone, Cialis, Viagra, Levitra), sickle cell crisis, penile artery injury, overstimulation with erectile aids (Triple-mix, Caverject, MUSE), and other causes. If you think you have a priapism, find an emergency room for immediate evaluation.

Phimosis is the condition where the foreskin cannot be retracted behind the head of the penis, or “glans”. If circumcised, this is not an issue since there is no foreskin to pull back. In some boys, the circumcision leaves a little skin to ride up over the head, but even so phimosis is very unlikely.

For very small boys less than two years of age, it is normal to not be able to pull the foreskin back. Babies almost never can have the foreskin pulled back without some manipulation and stretching. But when a boy gets older, the foreskin gets thicker and more elastic, and it should be possible. By the time potty training occurs the boy should be taught to pull the foreskin back to bathe and to dry afterward, and when urinating so that the foreskin stays dry most of the time. In this age group adhesions between the glans and the foreskin may prevent pulling the foreskin back, and a urologist can help with advice to alleviate these. Sometimes the adhesions are relieved with daily application of a cream, or by a small procedure. 

Older boys and men who have phimosis can try special creams with daily manipulation of the foreskin to stretch it over time. If problems with sexual activity or balanitis (an infection of the foreskin) become more acute, circumcision can be discussed. Balanitis is sometimes present in obese men with poorly-controlled diabetes and these situations are difficult to resolve because suprapubic fat rides up over the penis and complicates the effort to keep the area clean and dry.

Phimosis in older men who never had problems when younger is also relatively common, and is sometimes due to changes in the foreskin epidermis called balanitis xerotica obliterans (BXO). The only relief from BXO is circumcision, or a partial circumcision called a “dorsal slit”.

The foreskin on the end of the penis will trap old sloughed skin and will remain moist if the foreskin is not retracted and cleaned periodically. The white material that collects under the foreskin is called smegma. Fungal infection due to chronic moisture there is a problem for some men. Either or both can have an odor. An infection of the foreskin from bacteria or from fungus is called “balanitis”.

All boys and men after a certain age should be encouraged to retract the foreskin when in the shower or bathtub and to wash this area well. The foreskin should also be pulled back for drying with a towel after washing. Pulling the foreskin back while urinating is also advised so this area stays clean and dry as much as possible all day. But make sure to pull the foreskin over the end when done! 

If the foreskin cannot be retracted, that is called “phimosis”. If you pull the foreskin back and leave it that way too long (think hours), then it can swell and not want to go back over the end of the penis. This is called “paraphimosis”. You should think to see a urologist if you have balanitis, phimosis or paraphimosis.

The prostate gland acts as the point where semen is mixed and introduced into the urethra where it is ejaculated during orgasm. It is about the size of a walnut and it sits right underneath the bladder. The urethra passes through the center of the prostate and urine flows through it when the bladder is emptied. The ejaculatory ducts from the prostate enter the urethra in the middle of the gland. The purpose of the prostate is to provide chemicals important for sperm to work properly for reproduction. The external sphincter that holds urine in the bladder is below the prostate, so the prostate and bladder have to work together for a man to be continent.

Ureteroscopy is done to inspect the ureter, which is the tube that drains the bladder to the kidney. This is done using either a rigid or a flexible scope, depending on what the purpose of the procedure is and how far up the ureter the work is done. Most ureteroscopies are done for removing stones from the ureter or kidney. Others are done for diagnostic purposes such as biopsies. Some are done just to monitor a patient with ureteral or bladder cancer. 

Benefits of ureteroscopy are that it is an excellent way to clear ureteral stones and small kidney stones. It allows visual inspection of the ureter and kidney in a way not possible with radiologic procedures. Strictures and other injuries of the ureter can be inspected and in cases where it is needed, biopsies can be done. Laser fibers and stone baskets can be passed through the scopes permitting lithotripsy and stone basket extraction of stones. 

The risks of ureteroscopy are in addition to the risks of cystoscopy. In passing an instrument through the ureteral orifice and into the ureter, this opeing in the bladder can be torn or stretched. The ureter can be torn from the kidney or the bladder, and it can be torn open in the middle. If this happens and the problem is minor, a stent can be left while the ureter heals. Sometimes the injury can be extensive enough that open surgery could be required to repair the ureter. Sometimes the ureter is obstructed by stones or cancer and ureteroscopy fails to open a path for the kidney to drain. In this case a referral to a radiologist that day would be made for placement of a nephrostomy tube to drain the kidney directly. Every surgery has risks of acute or chronic pain, infection and bleeding – this one is no different. Blood may be seen in the urine for a while after ureteroscopy. A stent may need to be placed in the ureter at the end of the procedure, and this can cause discomfort and mild bleeding too. Strictures that narrow the ureter can occur weeks to years after ureteroscopy. 

Risks are managed with careful attention to detail during surgery, and appropriate antibiotics and medications afterwards. The problems of ureteroscopy do not surface often, but it is best to be prepared prior to moving ahead with this procedure. If a thousand procedures are done, some of these complications will occur to a few people because everyone and every situation is slightly different and some procedures are very technically difficult.

Maybe so, maybe not. Usually the advice when trying to pass a stone is to urinate into a strainer, so that you can see the stone(s) when they pass out the urethra. If you don’t use a strainer you might not see or feel small pieces. Sometimes a person who has a stone and is in a lot of pain eventually stops having pain. The pain is caused by swelling of the kidney by the urine as it backs up behind the stone. Eventually the pain can subside, even if the stone has not passed. The kidney in this situation is not able to drain urine, and it slowly starts to lose function. After a few months it can stop working altogether. It is very important to get a checkup and have the appropriate imaging studies to make sure that there is no urinary obstruction even if the pain has gone away when trying to pass a stone.

The ureters are actually quite thin, but they are pretty good at propelling urine down toward the bladder with peristalsis. Even a small stone can cause pain, which is from intermittent obstruction caused by the stone as it haltingly works its way down. There is a very good chance you will pass that stone without a surgery, but it may take a while. A small percentage of little stones (3 to 5 mm) get stuck in the ureter and require surgical treatment of some kind. The pain is caused by swelling of the kidney as the stone gets stuck and the urine backs up. Your urologist is probably expecting you to wait for a period of time and then followup – make sure you do that even if you pass the stone.

If you are passing multiple small stones it is possible that you have a larger problem. For one you might have a tendency to form stones that can be treated. Also you could have obstruction of parts of the urinary system. Obstruction that arises slowly is not always painful. Go see your urologist; make sure nothing worse is going on. If you don’t understand the underlying cause or don’t know the extent of the problem, you could do yourself harm.

The basic problem is that the kidneys are releasing more minerals than the urine can hold in concentration. The chemistry is complex, but the root of the problem is that the urine is precipitating crystal. The kind of crystal varies with the amount of minerals excreted by the kidney, the pH of the urine, and other factors. That is why drinking a lot of water to make the urine more dilute is the first step to preventing stones in the urinary tract.

Please visit a urologist in your area. Newborns may have an undescended testicle but almost all boys should have it drop to the scrotum by one year of age. An undescended testicle at an older age has an increased chance of cancer later in life. But this does not mean it will become cancerous. If the testicle were in the scrotum it would continue to function and you could check periodically to see if a cancer were developing. If you are older than one year and have an undescended testicle then you should definitely see a urologist in your area to either perform orchiopexy to put it down in the scrotum, or have orchiectomy to remove it. Which one is right depends on factors you can discuss with your urologist.

If you think there is a lump on your testicle, it could be cancer. Testicular cancer grows slowly at times, and quickly at others. Some lesions are benign, meaning that they are bothersome, but won’t spread. Others are malignant and have potential for great harm. There are many examples of a person having a problem and not noticing it until they have an “event” like falling off of a bike. The best way to be sure is to visit your urologist. They will be able to examine it and see what it is all about. They might even order an ultrasound of your scrotum to see what it looks like inside and help make the decision easier. Hopefully it will turn out to be a cyst or fibrotic mass and not cancer at all.

Prostatic tissue responds to the level of testosterone in the body as a result of testosterone being converted to DHT, which stimulates the prostate directly. A man with prostate cancer should not be given testosterone therapy for this reason. However, testosterone therapy does not cause prostate cancer or raise its risk – it simply can worsen the situation when it arises. If a man with low testosterone has been treated for prostate cancer and is considered at low risk for recurrence, then testosterone replacement can be discussed and carefully considered.

No. If testosterone levels are normal, then supplementing it can cause harm. It can be associated with azoospermia, blood lipid changes, sleep apnea, polycythemia, and worsening of prostate or breast cancers if they exist. Therapy should be reserved for those patients with a low level and symptoms associated with a testosterone deficiency after an appropriate workup to ensure that it is the right choice for them.

Testosterone is a hormone secreted by the testicle. It is under regulatory control of other hormones in the body. The hypothalamus in the front of the brain secretes GnRH. Stimulated by this the pituitary gland at the base of the brain secretes FSH and LH. In response to LH stimulation the testicle secretes testosterone. When testosterone levels rise the pituitary and hypothalamus lower GnRH and FSH/LH production, thus lowering the signal to produce testosterone. With all of this in balance the testosterone level varies over the course of the day within a normal range. In adults testosterone has a dozen or more functions. It is needed for sperm development, is involved in mood and energy levels, helps maintain muscle activity, and affects libido.

Testosterone therapy primarily improves mood, energy level and libido. It can also increase lean body mass while lowering body fat. It also can help with bone remodeling and improves bone mineral density.

Foremost is recurrent monitoring to see that testosterone levels are appropriate and not too high, or too low. Side effects of therapy should be monitored, such as breast enlargement, acne, skin irritation, infections at injection sites, or mood changes. The timing of the testing depends on the delivery system employed. Men on testosterone therapy will have digital rectal examinations and PSA tests every 3 to 6 months at first and then annually when over 40.

Testosterone can be given a patient with low testosterone due to primary testicular failure. The methods vary, but include oral agents, injections, patches, and gels. Oral agents are consumed quickly by the liver, so high doses are needed. Intramuscular injections have the benefit of lasting longer as depot injections can slowly be activated by the body, allowing normal levels to last as long as a month after an initial peak. Patches are adequate but sometimes cause skin irritation. Gels are relatively new but are effective, but caution is needed to prevent getting the gel on anything other than the patients own skin. Also available are pellets that are injected under the skin. Which choice depends on the patient and individual goals of therapy.

Like most problems, a detailed history and physical examination with the doctor in the office is an essential start. A discussion will be had of sexual desire and performance, along with a review of secondary sexual features such as strength, energy level, and hair growth. Lab tests of total serum testosterone will be taken in the morning. Other hormonal tests may be taken as well depending on the history. If prolactin is high there may be a pituitary problem, and if low then LH helps determine if the body is asking the testicles to make more testosterone. If LH is high and testosterone is low, this means that the testicles cannot produce enough testosterone to satisfy demand. In this case replacement therapy is indicated.