Ureteroscopy: Background and Current Controversies

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MINIMALLY INVASIVE STONE SURGERY (Ureteroscopy)

(Images of surgical equipment featured in this article are for patient education only. They are not intended for promotional use or a reflection of personal preference. We accept no fees or other benefits from vendors or their agents.)

Evolution of Technique

The fascinating history of urology with its captivating depictions, texts and stories rivals any other field in medicine. In particular, the ancient past of lithotomy (treatment and removal of urinary stones) dates back to Mesopotamia (3200 BC)and descriptions and treatments for urinary stone disease have been identified from ancient cultures including Hindu, Greek, and Egyptian. The treatment of stones, which at the time most commonly occurred in the bladder, was very dangerous, often lethal.  As such, it led to the development of one of the first medical subspecialists, the lithotomist, who opened the urinary tract and removed stones directly. Recognition of this unique set of skills earned a distinction in the Hippocratic oath, still recited by graduating students: “I will not cut for the stone, but will leave this to be done by practitioners of this work…”

Today, “cutting for stone,” otherwise known as open stone surgery, has been replaced by alternative minimally invasive techniques. Critical to this change has been the introduction of the endoscope. Whereas early pioneers such as Howard Kelly (depicted above in the early 1900’s using a wax tipped catheter in the ureter to detect a ureteral stone) relied heavily on intuition, feel, and clinical suspicion, advances in endoscopy have made it possible to inspect all parts of the urinary tract directly.Screen Shot 2016-01-19 at 1.56.38 PM

The particular endoscope that has revolutionized our ability to treat kidney stones in a minimally invasive fashion is the ureteroscope. Incorporation of its use into urologic practice has led to the development of a unique subspecialty, endourology, that focuses on minimally invasive and endoscopic surgical treatments.

Modern Ureteroscopy

A ureteroscope, as its name implies, is an endoscope designed to visualize and work within the ureter. Other scopes commonly used by urologists and endourologists include the cystoscope (used in the bladder) and the nephroscope (used in the kidney).

Although such scopes now enable modern surgical stone treatment, they have only been routinely utilized for the past several decades. Minimally invasive kidney stone treatment began in the mid-1980’s with shock wave lithotripsy and percutaneous nephrolithotomy. Ureteroscopy for treatment of ureteral stones was not performed routinely until then as well, and it was not until the late 1990’s and early 2000’s that ureteroscopes could routinely access and treat stones in the kidney. In the United States we often take such technologies and treatment options for granted, but open stone surgery is still practiced in many parts of the world where modern technology remains limited.

There are two types of ureteroscopes, rigid and flexible. Rigid ureteroscopes, as their name implies, are firm and preferred for treatment of stones lodged in the lower ureter which can usually be accessed in a straight path. When stones are located in the upper ureter and/or kidney, they often require Screen Shot 2016-01-19 at 2.09.57 PM
flexible ureteroscopes that accommodate to the shape of the ureter and renal collecting system (figure on right).  Though more difficult to maneuver, flexible scopes allow the urologist to inspect nearly the entirety of the inner kidney to find stones, treat them, and remove them using a variety of techniques. Innovation this area is brisk and modern digital ureteroscopes offer increasingly superior image quality, lighting and wide fields of view.

Fiberoptic vs. Digital URS

(Figure – Left ) Ureteroscopic image of the renal collecting system using older generation fiberoptic ureteroscope (left) and newer generation digital ureteroscope (right).  Note the superior image quality, increased light intensity and wider field of view.  Panels A and B feature small stones attached to a renal papilla.  Panels C and D feature the endoscopic appearance of Randall’s plaque.

 

Irrigation and Access Sheaths

In order visualize anything at all, fluid must run continuously through the scope and into the kidney to wash away blood, debris, and crystals that impair visualization. To accomplish this, the fluid (most commonly saline) is hung from a bag and run through tubing directly into the body of the scope where it comes out the tip and into the kidney.

This inflow is harmless, but excess filling of the kidney because of high pressure inflow or an inability of the fluid to freely exit around the scope can overstretch the kidney and cause fluid absorption, leakage, bleeding, and small tears within the kidney itself, a term we call extravasation.

To prevent this, many urologists use a device called a ureteral access sheath. This can be thought of as a temporary tunnel from the bladder to the kidney which allows any fluid that is irrigated into the kidney to quickly wash out around the scope, optimizing visualization and decreasing the likelihood of extravasation. The scope can be passed back and forth without rubbing against and potentially damaging the lining of the ureter, which is generally around the same small diameter as the scope itself. When used appropriately, temporary sheaths are safe and decrease postoperative infections and sepsis. While the majority of urologists routinely use them during ureteroscopy, debate does exist within the community as to whether or not they are required in every case.

Screen Shot 2016-01-20 at 11.41.49 PM(Figure on Left – Boston Scientific Navigator HD TM, Marlborough, MA)

The concern with routine use of a sheath is trauma and injury to the ureter when the sheath is passed. Larger diameter sheaths are preferable for procedures, but the ureter is quite narrow and often will not accommodate a large sheath and sometimes any sheath at all. In such cases, surgeons have several options.  If they deem a sheath necessary, they can place a temporary ureteral stent that lets the ureter passively dilate and facilitate sheath placement at a later time. Alternatively, they can dilate the ureter during the procedure using either balloon or serial dilators in order to get the sheath up.

Screen Shot 2016-01-29 at 10.07.22 AM

(The ureteral access sheath (white arrow) is passed under fluoroscopic guidance over a wire (black arrow) that is positioned from outside the body and extends through the ureter to the kidney.)

Because the ureter is delicate and easily torn and injured when overstretched, there is risk.  In a recent publication by Traxer et al. that describes 359 consecutive cases of ureteroscopy where a ureteral access sheath was used, nearly half (46.5%) of the patients had some degree of ureteral injury. Most injuries were superficial, but severe injuries were found in 13.3%. The main figure (below) from this paper often presented at society meetings, particularly by those who do not favor sheath use.

Screen Shot 2016-01-20 at 11.27.46 PM

While these images raise concerns, there is no evidence to date that when managed properly with placement of a temporary ureteral stent these injuries produce any long term consequence. For example, there is no published evidence of an association between ureteral access sheath use and ureteral stricture. Most studies have shown that intraoperative complication rates during flexible ureteroscopy are no different with or without an access sheath.

Alternatively, urologists have the option of performing ureteroscopy without using a sheath at all.  One advantage of this approach is that the ureteroscopes themselves are thinner than the sheaths and thus more likely to be able to be passed up the naturally thin ureter without trauma or need for dilation.  This approach does have limitations though including poorer visualization, higher potential for excess intrarenal pressure, and a limited ability to make multiple passes back and forth between the kidney and bladder to remove stones.

Lasers and Baskets

Many instruments, all are extremely thin, can be passed through the small working channel that runs from the back of the ureteroscope outside of the body, to the tip of the scope in the kidney. They are used to fragment and remove stones.

Stone retrieval baskets, pictured below, (Cook Medical, Bloomington, IN) are opened and closed by an assistant to ensnare stones and remove them from the kidney. They come in various shapes, sizes and configurations. When stones are roughly 2-4 mm the basket is able to remove them intact.  When stones are larger, they must be fragmented into smaller pieces in order to be removed or pass.

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The most commonly utilized method to fragment stones during ureteroscopy is laser lithotripsy.  Several lasers exist for the purpose but the most popular one by far is the Holmium laser. The Holmium laser can safely fragment any type of stone. The laser delivers short bursts of light energy through water that destroys the stone’s structure by creating a micro explosion of intense heat, pressure, and cavitation bubbles. Because the laser energy penetrates less than half of a millimeter deep it causes minimal damage to surrounding tissues.

Screen Shot 2016-01-21 at 12.59.51 PM

(Dornier Medtech, Friedrichshafen, Germany)

Ureteroscopic Stone Treatment Techniques

As ureteroscopic technology and familiarity with this approach to treat stones continues to grow, the relative number of stones being treated in this fashion has been growing rapidly as well. The latest estimates of surgical practice from the past decade show that ureteroscopy has replaced shock wave lithotripsy as the most commonly performed treatment of kidney stones, accounting for 54% of upper urinary tract stone procedures. Along with the widespread adoption of this procedure, two main techniques have evolved into practice, the optimal one of which remains unclear.

Active Extraction

Active extraction means to remove every piece of stone from the kidney so that at the end of the procedure there are no remaining stones and patients do not pass any stones postoperatively. Critics raise concerns that this technique requires a ureteral access sheath, an assistant to operate the basket, and potentially increases the operating time. A video description of this technique prepared for this article can be seen below.

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Stone Dusting

Stone dusting is conceptually different from active extraction because the goal of the procedure is not to remove all stones directly but rather fragment them into minute pieces (dust) that can then be passed after the procedure, painlessly and without consequence.

Because his technique needs no access sheath, being performed with single pass of the ureteroscope, it benefits patients with narrow ureters.  The surgeon can dust with only a laser and avoid a basket with its cost of disposable equipment and need for a skilled assistant. Here is a video of the procedure prepared by Lumenis Ltd, Israel.

[youtube id=”ooj9d_f81MY”]

Which Technique is Best?

Urologists debate whether active extraction or dusting is the better treatment approach, and both sides have their staunch advocates. As is common, the intensity of debate reflects the paucity of studies that compare the two techniques.

Interim results from an ongoing study by the Endourology Disease Group for Excellence (EDGE) comparing dusting to active extraction (table) indicate that dusting is associated with a shorter operative time (40.5 vs. 59.8 min) despite being used to treat larger stones (113 mm2 vs 81mm2).

Screen Shot 2016-01-21 at 3.08.58 PM

On the other hand, a greater percentage of patients treated with a dusting had residual (leftover) stones after the procedure than those treated using active extraction (39.1% vs 11.1%).

These residual stones were not just dust; 44% of the stones were greater than 4 mm.

Despite the higher rate of residual fragments in the dusting group, only one patient in each arm suffered symptoms from a residual fragment at short term follow-up, raising the question of whether or not small residual stones are clinically significant.

But these clinically insignificant residual fragments (CIRFs)’ may not be clinically insignificant.

In one recent study, the EDGE working group found that 44% of 232 patients who had ureteroscopic stone treatment and were found to have residual fragments experienced a “stone event” (defined as a composite of stone growth (at least 1 mm), stone passage, re-intervention or postoperative complications) at mean follow-up of nearly 17 months. Of these 29% required a surgical intervention.

The likelihood of stone events and reintervention were depended on the size of the residual fragment. Among patients with fragments greater than 4mm, reintervention was required 38% of the time and complications related to the fragment occurred 59% of the time. Second surgical procedures occurred sooner in patients treated with a dusting technique compared to those treated with active extraction but the statistical significance of this difference was uncertain.

Portis et al. found that among 218 patients treated with ureteroscopy and active extraction residual stones predicted need for retreatment. At a median follow-up of 4.1 years, patients with residual fragments less than 2mm in size required retreatment 2.4% of the time, compared to 19% among patients with residual fragments 2 to 4 mm in size, and 46% among patients with residual fragment greater than 4mm. Rebuck et al. found a nearly 20% likelihood of retreatment for residual fragments less than 4 mm after ureteroscopy at a mean of 1.6 years.

All in all, both sides in the debate can find reasons for their position. Active extraction leaves behind fewer fragments, but so far in a head to head trial need for less secondary surgery has not been documented. Dusting avoids the cost and complexity of the basket and the sheath, but in the long term may condemn patients to more followup surgery. Time and trial will tell, ultimately.

Follow-Up After Ureteroscopy

Oftentimes urologists will leave a temporary ureteral stent to prevent swelling of the ureter as a result of the procedure. This use of stents is a source of controversy worthy of a future post.

All agree one needs follow-up imaging of the kidneys to tell whether or not stones have been fully removed and whether or not a ureteral stricture (scar) has caused obstruction and  kidney swelling (hydronephrosis), a complication that occurs 1-4% of the time.

Ultrasound Imaging

Ultrasound is relatively inexpensive, requires no radiation, and offers very detailed images of the kidney to determine whether or not there is hydronephrosis. But it is not very accurate at identifying residual stones, particularly small ones. It is also operator dependent and results can vary based upon the experience of the sonographer performing the examination.

KUB X-Rays

Ultrasounds are commonly combined with a kidney x-ray (commonly referred to as a KUB) which is also inexpensive and better at detecting stones with minimal radiation.The majority of published studies to date that have assessed stone free rate after ureterscopy have used KUB/US to determine the presence of residual fragments. Stone free rates using this imaging endpoint are commonly found to be in the mid 80-90%; even for large stones greater than 2 cm in size.  

CT Scans

CT scans are the best test to identify stones, but are more expensive and are associated with higher degrees of radiation. Those studies that have used postoperative CT scans to identify residual stones demonstrate much lower stone free rates, commonly in the range of 50%.  Interestingly the difference appears to be in the small stones <4 mm more likely to be seen on CT scan over KUB/US. If these stones are not taken into consideration, CT scan follow-up would otherwise be on par with that reported in the KUB/US series.

Although the question of whether KUB/US or CT is a better follow-up test is an important one, the more important question is whether or not routine imaging is being performed after the procedure at all. Despite recommendations by the American Urological Association that all patients should undergo at least a minimum of an ultrasound after ureteroscopy (see figure below) ,a recent study from the Cleveland Clinic found that fewer than half of all urologists routinely obtain any postoperative imaging whatsoever.

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Take Away Messages

The goal of ureteroscopy should be to render the patient stone free 

Regardless of the technique used, the ultimate goal of the procedure should be to leave the patient with no stones. Residual fragments are likely sources of future stone events. Therefore removing all stones should improve long term outcomes.

Urologists should be familiar with all ureteroscopic treatment techniques

Results of studies such as the EDGE group comparing dusting and extraction will determine the gold standard ureteroscopic treatment technique. In all likelihood though, we will come to realize that ureteral anatomy, width, and ability to pass an access sheath as well as the stone themselves will mandate one technique over another for any one patient.

Soft stones, for example, are more likely to fragment to true dust and thus may be more amenable to dusting. Harder stones are more likely to fragment into large pieces and thus benefit from active removal. Infection mandates complete stone removal, potentially harder to achieve with dusting. Alternatively dusting does not require an assistant and thus may be the only feasible option in instances where extra help is not available.

The ureteroscopy should not be the end of the story

Nephrolithiasis often manifests as an acute event ending in ureteroscopy; however, it is increasingly recognized as a chronic condition. As such, it is critical that surgery to remove the stone is not the end of the relationship with the patient.

Residual stones commonly lead to clinical events greater than one year from the time of the initial procedure including growth, passage, and need for retreatment.

Stone disease is chronic and recurrent, and the least desired outcome is formation of new stones after stones have been removed. As many as 50% of first time stone formers will recur within 10 years highlighting the significance and potential benefits to dietary counseling, metabolic testing, surveillance imaging, and other practices to prevent and detect stones over the long-run.

The main thrust of this entire site is toward prevention, before surgery is ever needed and with especial need after a successful surgery so that another need never be performed.

67 Responses to “Ureteroscopy: Background and Current Controversies”

  1. Janet A Zander

    I am a 60 year old female, overweight, but generally in good health, low cholesterol (170), no diabetes, excellent blood pressure, I do water aerobics several times a week, more in the summer. I have had a seizure disorder since I was small child controlled by medication, no seizures in 30 years. In 2009 my neurologist switched me from dilantin to topiramate 400 mg daily. One of the side effects of topiramate is the formation of kidney stones and I believe this is because it seems to suppress my thirst. I have to force myself to drink. I am never thirsty, I don’t drink soda, coffee, much of anything. In 2011 I developed my first kidney stone, 6mm, which was dusted and removed with the ureteroscopy and stent procedure. I became a regular customer, every 2 years 2013, 2015 and now just yesterday, Sept 20, 2017! I have a new urologist who told me that I need to change my diet because my stone is an oxalate stone. I “thought” I was eating healthy-lots of whole grains, dark leafy greens, fruits and vegetables, nuts, all of which seem to be full of these oxalates! After reading this article I still plan on changing my diet but I wonder if I am just the perfect storm for these stones. The topiramate, the lack of liquids, the residual from the dusting, the previous diet. My last stone was 9mm. I have no family history of these at all but would appreciate any insight.
    Thanks
    Jan

    Reply
    • Fredric Coe, MD

      Hi Janet, I am afraid the cause of stones with Topiramate is not reduced fluids but inhibition of renal carbonic anhydrase leading to renal tubular acidosis and calcium phosphate stones. It is the drug and the drug must go. All the diet changes will not protect you. Change the drug. Regards, Fred Coe

      Reply
  2. Kerry Bloomer

    My wife had a kidney stone removed via ureteroscopy but the Urologist neglected to remove 2 other stones 5mm in size that he informed my wife may or may not cause issues in the future and that he could do the procedure again to remove them. I have developed a major anxiety as a result of this and wanted to accompany my wife into her next procedure to remove them. So far I have been stonewalled to the extent my wife doesn’t even want to try. Is there a facility in North America that will allow a family member (spouse) to observe the procedure thereby significantly reducing the stress on the patient and the spouse. We live in Edmonton, Alberta, Canada but are willing to travel anywhere in North America to have the process done with me ( her spouse) in attendance. Thank-you

    Reply
    • Fredric Coe, MD

      Hi Kerry, In general the OR is not a good place for spouses. But also, if one asks for all stones to be removed one can expect that to happen. If you can travel in the US and get care, I can help you find very high quality surgeons who will render kidneys stone free. Just let me know. By the way be sure she is getting preventive care; nothing is more unnerving than new stones to replace the old ones. Regards, Fred Coe

      Reply
      • Kerry Bloomer

        Is it possible to arrange for a spouse to go into the OR under certain circumstances. Lithotripsy is also an alternative but it has also been moved into the OR in Canada further restricting my access. I have been present for a lithotripsy 30 plus years ago when it was first introduced. I have been looking at numerous studies and medical papers as of recently and have found that have a family member present during the procedures is healthier for the patient and their family member, significantly reducing stress on both parties and reducing recovery times. The main caveat on this is that Physicians are uneasy having a family member present which has be identified as the prime reason procedures have been placed behind the facade of the OR. It is this reason that the battle currently exists between patient’s rights to choose who is in attendance and the Physician’s personal feeling of angst. There have been many comments of anxieties of spouses that have made the procedures more difficult for the patient. I thank you for your response to my query. It appears that I have a long road ahead of me in my search. I have started searching in the UK where some of the family presence studies have been conducted. Patients and their families shouldn’t have to undergo this pain for a procedure that has no clinical bearing on who is in the room.

        Reply
        • Fredric Coe, MD

          Hi Kerry, You raise an interesting question. Having been in many OR sessions as a physician with my own patients, I can offer a few ideas. They are busy and crowded places, and the staff needs to speak to each other and work with as little friction as possible. If there is anaesthesia, the patient will not know who is there. With lithotripsy it is perhaps less of a problem. How about as a compromise you might ask to watch the live video? Of all my concerns the worst might be distraction of surgeons that lengthens OR time and anaesthesia time for the patient. Most surgeons, by the way, and proud of their technical abilities and all to happy to demonstrate and converse. Good Luck, Fred Coe

          Reply
          • Kerry Bloomer

            I have been in my wife’s lithotripsy in the past and 3 colonoscopies and the surgeons that provided the procedures had no issues in me being there and exuded a great deal of confidence in their abilities. In each case my wife and myself were both relaxed prior to, during and after the procedures as we weren’t anxious with the support given to each other. Having a surgeon feel distracted while performing a procedure with a spouse present would have me questioning their confidence in their own abilities. Coming from an Engineering career scenario (I am not a professional Engineer), the best engineers I have found welcomed the presence of an observer of their work as it provided them the ability to present their capabilities. Those that didn’t like having an observer generally felt they were being tested and were generally the ones that made the most errors of which I had to go in after to correct. As far as my ability to manage the activity on my wife which would possibly be an issue, I would have to say that strengths in that area could match any nurse or physician in the OR as I have seen some major blood and gore on family members in a hospital ER’s over the years.

            Reply
            • Kerry Bloomer

              I would like to thank you for listening to my comments and providing input. My wife has decided at this point to do nothing and hope for the best.

              Reply
  3. Maria S Varnalis

    I have a 10mm kidney stone on my left kidney towards the bottom of the kidney… scheduled to have lithotripsy… so I have anything to worry about? I am healthy otherwise… just worried about trauma that might be caused from the shockwaves, Afterwards the Dr. told me to drink lots of water and stand on my head! for awhile so that the stones flow upwards and leave the kidney.

    Reply
  4. JPD

    I had a ureteroscopy with laser 12 days ago. Doctor said they had to blast the stone first ( 5mm x 4 mm) and remove the pieces. This was my 2nd ureteroscopy as my first was 6 years ago from which I had a quick recovery. This time I am having a MUCH tougher time. Stent was removed after two days which was the most painful and horrifying two minutes of my life and I have been through 40 stones in my life so I know pain well. Since then, I have periodic but brief sharp pain when sitting on hard surface or bending over. Also have pain every single night for last 10 days when the area of the surgery “wakes up and stretches out”. Any attempt at activity with my wife is also painful. My urologist last week just said “give it time” and I should be fine. Is such pain normal for some patients or should I see a new urolologist ? I’m fearful of this never healing if something happened during surgery.

    Reply
    • Fredric Coe, MD

      Hi, I suspect your urologist is right and things will gradually heal up. But 40 stones is so many, you should really push at prevention. If you have not seen it, here is a good plan. You should not need to make so many stones – even any is too much. Regards, Fred Coe

      Reply
  5. Raquel D

    Thank you, Dr. Coe. So what might that mean for my diet? Any specific plan I should adhere to at this point?

    Reply
    • Fredric Coe, MD

      Hi Raquel, As I remember your lab data results were normal and it seemed your stones might have formed in the past. I would have a new 24 hour urine when you are recovered from surgery and of course have the removed stones analysed. If results of the urine remain normal merely maintain a high fluid intake. But it is your physician who is in charge and what I say is from a great distance and merely commentary. Regards, Fred Coe

      Reply
  6. Nihal

    Dear Dr. Coe,

    So on the Feb 28 reply, you had recommended I do a 24 hour urine to check my pH (among other things). My urologist says he will order 24 hour urine, only after surgery. I would like to see if I can melt this before doing any surgery, because my average HU densities are 350 and 450 HU (see earlier post) and my home pH measurements are below 5.5. So I got my family Dr. to order the 24 hour urines. I have some doubts as to whether he ordered the right ones to get all the info that is needed for a full evaluation. Following are the tests he ordered. Can you confirm that this covers everything including pH, SS values, and any other data that is needed for a full evaluation for any kind of stone? If these are not the right ones what should he have ordered? I would appreciate if you can respond quickly since I would like to start the collection process as soon as possible. I am in Illinois USA.

    1. UR 24 hour Calcium
    2. UR, oxalate 24 hour, MAYO OXU
    3. UR 24 hour uric acid QUANT
    4. UR 24 hour creatinine

    Thanks
    Nihal

    Reply
    • Fredric Coe, MD

      Hi Nihal, No they are not related to uric acid stones as there is no pH. Likewise, most physicians order kidney stone panels – complete arrays of testing that bundle pricing so as to get the most from what you pay. Quest and LabCorp offer these. You do not know the stone type either, because HU are only approximate. More: I am far from your care as I know nothing except what you have sent, and I fear becoming an intruder. Might I recommend that before the surgery you seek a second opinion at a recognized university based kidney specialty program, just to be sure of everything. Regards, Fred Coe

      Reply
      • Nihal

        Dear Dr. Coe,

        Thanks for the response. Is the following the right test from Labcorp?
        http://www.labcorp.com/test-menu/30091/kidney-stone-urine-test-combination-with-saturation-calculations

        With regard to a recognized university based kidney specialty program, would you be able to recommend a Dr. in the Bloomington, IL, Decatur, IL, Peoria, IL, Champaign/Urbana, IL, Peoria, IL, Springfield IL. areas?

        Thanks
        Nihal

        Reply
        • Fredric Coe, MD

          Hi Nihal, If it is LabCorp you want their Litholink product. It is more polished and priced the same. I looked on the map and you live in an unfortunate place. You are about equal distance – and considerable – from our center in Chicago and the other center in Indianapolis – but the INDY one looks easier to get to. One or the other would be right for you. If it is INDY, let me know and I can help make an introduction. If Chicago is not too hard, the same. Regards, Fred Coe

          Reply
          • Nihal

            Dear Dr. Coe,

            Actually Chicago is closer to me. Whom do I contact to setup something? Do I get to see you or someone else? As you might understand, I would have to investigate the affordability, since I am pretty sure my insurance won’t cover the bulk of it, since you would be considered “out of network”.

            Thanks
            Nihal

            Reply
            • Fredric Coe, MD

              Hi Nihal, Kathleen Dineen can make all arrangements: 773 702 1475. She can also help with the financial issues. I would see you myself. Regards, Fred Coe

              Reply
  7. Raquel D

    Thank you for the response, Dr. Coe. So it turns out I had the procedure yesterday. Urologist was able to remove seven of the 10 stones in my left kidney. THREE remain imbedded deep in the kidney tissue. Can I expect these will cause problems there? Thanks again.

    Reply
    • Fredric Coe, MD

      Hi Raquel, The imbedded stones are probably either plaque or tubule plugs. Your urologist knows which. IN neither case will the material itself migrate. But if plaque new stones may form in it; likewise if plugs. Your surgeon could not have removed these without damaging kidney tissue. Regards, Fred Coe

      Reply
  8. Raquel

    Hi,

    I was just hoping to post numbers from recent 24-urine test and see if Dr. Coe sees anything that jumps out. I am scheduled to have a ureteroscopy on Thurs. to remove about 10 stones from my left kidney – several of which are in the 9 mm range. I’ve had these for at least four years. Tried lithotripsy four years ago – which didn’t work well. (biggest stone wsa 5 mm back then). Then decided to leave it alone until discomfort in recent weeks. We don’t know what kind of stones other than likely calcium (according to my urologist because they show up on the xray.) Does anything look odd here? The doctors I’m seeing don’t see anything obvious. I notice my ss caOx is LOW and Creatine slightly high but that’s all I see that raise questions. Any help you can offer is appreciated.
    Component Results
    Component Your Value Standard Range
    VOLUME, URINE 2.17 L/day 0.50 – 4.00 L/day
    SS CAOX, URINE 2.40 6.00 – 10.00
    CALCIUM, URINE 77 mg/day 0 – 199 mg/day
    OXALATE, URINE 27 mg/day 20 – 40 mg/day
    CITRATE, URINE 941 mg/day >=551 mg/day
    SS CAPHOS, URINE 0.20 0.50 – 2.00
    PH, URINE 5.895 5.800 – 6.200
    SS URIC ACID, URINE 0.69 0.00 – 1.00
    URIC ACID, URINE 0.598 gm/day 0.000 – 0.749 gm/day
    CREATININE, URINE 1445 mg/day mg/day
    SODIUM URINE 115 mmol/day 50 – 150 mmol/day
    POTASSIUM, URINE 64 mmol/day 20 – 100 mmol/day
    MAGNESIUM, URINE 49 mg/day 30 – 120 mg/day
    PHOSPHORUS, URINE 0.724 gm/day 0.600 – 1.200 gm/day
    WEIGHT 54.4 kg kg
    CREATININE/KG 26.6 mg/kg 15.0 – 20.0 mg/kg
    CALCIUM/KG 1.4 mg/kg 0.0 – 3.9 mg/kg
    CALCIUM/CREATININE 53 mg/g 0 – 139 mg/g
    AMMONIUM, URINE 31 mmol/day 15 – 60 mmol/day
    CHLORIDE, URINE 129 mEq/day 70 – 250 mEq/day
    SULFATE, URINE 30 mEq/day 20 – 80 mEq/day
    UREA NITROGEN, URINE 7.65 gm/day 6.00 – 14.00 gm/day
    PCR 1.1 gm/kg/day 0.8 – 1.4 gm/kg/day
    CYSTINE SCREENING, URINE Negative Negative

    Reply
    • Fredric Coe, MD

      Hi Raquel, These numbers and your story are consistent. The stones slated for removal have been present for 4 years or more and your lab data are all normal with low stone risk. I suspect your stones formed in the past when your urine chemistries were quite different. I am not sure why surgery is now being done, but be sure all material removed is analysed to find out what you are forming – or have formed. Possibly much of what is seen is in the kidney tissue. Regards, Fred Coe

      Reply
  9. Nihal

    I have been diagnosed with a 7mm stone in my Right kidney (CT scan showed between renal pelvis and lowest calyx). I am weighing my options as to whether to do a ureteroscopy or SWL. I know SWL lithotripsy is less invasive but I am a little worried about the damage it might do to my kidney and or other organs, especially pancreas. I read some article which said there could be some long term damage to organs. I have type II diabetes and even the notes handed out to me by the Dr’s office about SWL said there could be 30-40% increase in the risk for diabetes. I certainly don’t want my diabetes to get worse and or have any long term damage to my kidneys, pancreas or any other organ as a result of SWL. Then there is the question of the efficacy of SWL due to the location of the stone and well as the fact that they can’t seem to spot the stone in a Xray. Due to the above reasons I am leaning towards ureteroscopy. Can you comment on the effects of SWL in terms of long term damage to organs (especially pancreas and kidney)?

    Reply
    • Fredric Coe, MD

      Hi Nihal, A single stones that size can be disrupted by SWL or removed via URS. From a single treatment little evidence supports important disease in the pancreas. Overall, URS may be preferable if the stone is hard to see. This is an area where the surgeon doing the work is the best authority. Regards, Fred Coe

      Reply
      • Nihal

        Dear Dr. Coe.

        Thank you for the response. Like the concept of ureteroscopy, but dreading the stent aspect of it.

        1. Are there techniques to better visualize stone during ESWL? I’ve heard terms like intravenous pyelogram. Can this be used during the ESWL to target the stone?

        2. I took a closer look at CT. in the coronal view I see one bright spot (~7x7mm , 450 average HU) and in the adjacent plane, very close to the first one another bright spot (4x4mm, 350 average HU). In the axial view, it is one long, thin bright spot (11×2.5mm, 330 average HU) . So I am guessing one stone, long and thin in the axial view and much wider in the coronal view. Based on the above, how small do you think the average stone fragment sizes be after ESWL? 1mm, 2mm, 3mm or bigger or even smaller?

        3. Location of the stone is another concern, CT scan shows it is between renal pelvis and lowest calyx (more biased towards the latter). I feel that the stone fragments after ESWL will fall into the lowest calyx. Would they come out on their own or would I have to do a subsequent ureteroscopy anyway to get these stone fragments out?

        Thank you very much for the great service your are providing

        Nihal

        Reply
        • Fredric Coe, MD

          Hi Nihal, You are asking me things I cannot answer as I would have to see the images themselves. Even so, your surgeon is the key person, and I would bring these issues directly to him/her. With ESWL fragments do often lodge in the lower pole. I like ureteroscopy more because a stone free kidney is the usual outcome, but once again your surgeon wants a stone free kidney for you and may well have reasons to choose the modality, reasons I cannot know from so far away. Regards, Fred Coe

          Reply
          • Nihal

            Dear Dr. Coe,

            Thanks for the response. Based on the average HU density of the stone – 450 HU for part of the stone and 350 HU for other part of the stone (see more details above), can you say whether this is very likely to be an Uric Acid stone or not?

            Thanks

            Nihal

            Reply
            • Fredric Coe, MD

              Hi Nihal, Low density like this is likely to be uric acid, but when very small stone density can become uncertain. The issue does matter. If uric acid it can dissolve and that would make surgery unnecessary. Have you done 24 hour urines? If so, is your average urine pH below 5.5? This latter is crucial for it not below 5.5 uric acid is most unlikely. Regards, Fred Coe

              Reply
              • Nihal

                Dear Dr. Coe,
                Thanks for the response. I haven’t done a 24 hr urine yet, but will get one done soon. Urine pH seems to be below 5.5 from the spot checks I am doing at home, plus I am a type 2 diabetic.

                Let me introduce a twist. What about if there is blood in the urine? I have had visible blood in the urine in the recent past, but lately the urine has a yellow tinge (in spite of all the water I am drinking), so I am pretty sure there is some blood in the urine. Would this skew the urine pH? Do I need to subtract the pH effect from the blood (I am not sure if there is even a way to do this), or is it the composite urine pH with blood that I need to worry about? I would assume that the stone formed before it started bleeding, so if we were looking for a root cause we would have to subtract that effect. The confusion arises if the composite pH value were to come above 5.5. If the composite pH came below 5.5, then I would think the pure urine pH would be below 5.5 as well.

                If I need to compensate for the blood effect, is there some extra parameter I need to request in the 24 hr urine test in order to do some calculation to subtract that effect?

                Thanks
                Nihal

              • Fredric Coe, MD

                Hi Nihal, diabetes will lower urine pH and famously causes uric acid stones. Blood has so little buffer capacity in the amounts present in urine you can ignore it totally. Just do the urine and see what is there. Regards, Fred Coe

              • Fredric Coe, MD

                Hi Nihal, diabetes will lower urine pH and famously causes uric acid stones. Blood has so little buffer capacity in the amounts present in urine you can ignore it totally. Just do the urine and see what is there. Regards, Fred Coe

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