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Monday, October 15, 2012 - Director of DMC Kidney Stone Center Unveils A Powerful New Weapon against the Disorder
Breakthrough surgical study by Jason B. Wynberg, M.D., recently published in authoritative Journal of Endourology, could lead to “paradigm shift” in how urologists remove large kidney stones.

DETROIT – A just-published study by Detroit Medical Center (DMC) urologist and Director of the DMC Kidney Stone Center Jason B. Wynberg, M.D., describes a surgical technique that could make it much easier for urologists to remove painful, large kidney stones, while also significantly reducing the amount of radiation to which patients are exposed.

Dr. Wynberg’s breakthrough surgical procedure includes a new method for creating a small channel from the back to the kidney to remove large kidney stones. The channel is used in breaking the stones into fragments and then vacuuming them from the kidney. This access technique is much easier to learn and perform than standard methods and is described in a recent edition of the authoritative Journal of Endourology.

The standard method for creating a channel between kidney and back requires the clinician to advance a needle from the latter into the kidney. But that procedure is difficult, risks bleeding, and often exposes patients and surgical staff to high levels of radiation. Due to the significant difficulty of this technique, it takes physicians anywhere from 60-80 repetitions to develop a basic proficiency with it, on average.

As described in Dr. Wynberg’s recently published article (“Flexible Ureteroscopy-Directed Retrograde Nephrostomy for Percutaneous Nephrolithotomy” in the Journal of Endourology, the new technique simply requires the surgeon to advance a flexible ureteroscope (a thin telescope) into the kidney. That step, fortunately, is not difficult. Using direct vision on the video screen, the urologist then selects an “exit” point from the kidney and carefully maneuvers the end of the flexible scope into the proper position.

A thin, sharp wire is then advanced through the flexible telescope, through the kidney, and out the patient’s back. After that the thin wire is traded or exchanged for a slightly thicker wire using a special double catheter. Over this second wire, a balloon is passed – and this step enlarges the channel into the kidney. Once that is accomplished, a tubular sheath can be advanced into position between the kidney and the patient’s back. Through this sheath, telescopes and safe ultrasound instruments that break and remove large stones are inserted into the kidney.

This new procedure has the potential to benefit patients in several ways.

One great benefit stems from the fact that most urologists are unable to create their own channels into the kidney. As a result, patients most commonly have the channel created by radiologists under some sedation. Patients are then awakened and have a second anesthetic prior to having their stones removed by the urologist. This often results in more radiation exposure for patients – along with the added risk of undergoing two separate procedures.

Thanks to this new technique, however, the urologist will often be able to achieve access with patients remaining under the same anesthetic that is used in the stone removal procedure.

There is also the potential for better care . . . if a urologist selecting their own exit site for the channel succeeds in creating a better passage for stone removal, which will often be the case. Urologists at the University of Pittsburgh found that radiologist-obtained access may lead to stone-clearance that is inferior to the clearance that occurs when urologists themselves obtain their own access [J Endourol. 2010 Nov; 24(11):1733-7]. This study concluded: “Despite similar stone complexity and access difficulty, urologist-obtained access was associated with a statistically significant improvement in overall stone-free rate.”

Dr. Wynberg’s early data also suggest a dramatic reduction in radiation exposure to patients and surgical staff with this new technique. Radiation exposure has been linked with the development of malignancies in rare cases, and therefore attempts to reduce radiation exposure as much as possible are always of clinical significance.

Describing the new method for initial wire insertion through the urinary tract by means of a ureteroscope and then introduction of the catheters, Dr. Wynberg is careful to point out that this conceptual approach to kidney access was first described in 1989. However, the technique required further development to simplify it and improve success rates.

“What’s truly new about my approach is that for the first time it employs a new ‘co-axial catheter’ which allows the urologist to exchange the initial ‘thin wire’ for the standard-sized wire which is required to permit entry of the sheath through the back,” said Dr. Wynberg. In addition, Dr. Wynberg has defined appropriate patient selection criteria for this procedure, based on pre-operative imaging. Recently he has also been teaching clinicians how to perform extra low-dose fluoroscopy during the procedure, in order to better show the surgeons where the wire is travelling.

“I think this new approach could eventually lead to a paradigm shift in treatment of larger kidney stones,” said the DMC physician. “Using this method, any urologist could learn how to achieve the initial wire insertion during only two or three repetitions of the procedure – instead of the 60 to 80 repetitions that are required with older methods.

“If that happens, many urologists will no longer feel compelled to send kidney stone-removal patients to a radiologist for an initial procedure aimed at inserting the wire. And the benefits for patients are obvious. Instead of requiring two surgical procedures, they would undergo only one. And since the data strongly suggest that this approach results in better management of kidney stones, the potential for better outcomes is significant.”

Dr. Wynberg and his team have presented his early experience with this technique at several international kidney stone and urology meetings. He is now is looking forward to developing a kit with a surgical device company that will enable urologists to perform this procedure all around the world. The Detroit Medical Center looks forward to further leading-edge surgical research from Dr. Wynberg and the DMC urology team.

The DMC Kidney Stone Center also makes available to patients a clinical dietician to create customized stone prevention care plans based on a complete metabolic evaluation for kidney stone risk factors. For an appointment with Dr. Wynberg, call 313-274-4793.

About Detroit Medical Center  
The Detroit Medical Center includes DMC Children’s Hospital of Michigan, DMC Detroit Receiving Hospital, DMC Harper University Hospital, DMC Huron Valley-Sinai Hospital, DMC Hutzel Women’s Hospital, DMC Rehabilitation Institute of Michigan, DMC Sinai-Grace Hospital, DMC Surgery Hospital, and DMC Cardiovascular Institute. The Detroit Medical Center is a leading regional healthcare system with a mission of excellence in clinical care, research and medical education.