Open nephron-sparing surgery remains the most desirable for the patients

Aug 10 2005

Urologists often view less-invasive surgery techniques as more desirable for the patient, but in a study of open nephron-sparing surgeries (NSS) from 1985 to 2001 at Mayo Clinic, researchers found that the "gold standard" of open surgery for kidney tumors should remain the first choice for many patients. The study appears online today in The Journal of Urology.

"By comparing the first decade of elective open surgeries with more contemporary ones, we found that patient outcomes have greatly improved," says Michael Blute, M.D., Mayo Clinic urologist and lead investigator of the study. "This leads us to the understanding that while there are some new treatment options out there, what was once the only option (open NSS) is still quite often the best option."

Prior to 1985, open NSS was only done on patients with one kidney while patients with two kidneys and cancer in one automatically had the entire kidney removed. In the mid-1980s, Mayo Clinic began to use open NSS to treat patients who still had a healthy second kidney. This led to increased quality of life and fewer patients who subsequently had to resort to dialysis.

Since then, laparoscopy has evolved as another commonly used treatment, often considered superior in other types of surgery. Initial studies showed that laparoscopic NSS is feasible for small, easily accessible kidney tumors, making it appear the more favorable option. However, Dr. Blute and his colleagues have found that may not be true for many cases, especially when large or complex tumors are involved. "It's very difficult to safely and accurately remove a complex kidney tumor with laparoscopic NSS," explains Dr. Blute, "and if you find some cancer remaining when you look at the tissue under the microscope, it is difficult to remove more tissue like you can when doing an open NSS."

Dr. Blute and his co-investigators reviewed all open NSS procedures performed at Mayo Clinic between 1985 and 1995, and compared them to those performed between 1996 and 2001. They found that the procedure has gotten increasingly better results over time, and attributed this to increased surgeon experience, improved anatomical imaging, and enhanced perioperative care. For example, hospital stay declined from a median of seven days to five days, blood loss and transfused units of blood significantly decreased, early complications declined considerably, and urine leak occurrence was demonstrated in only 0.6 percent (compared to previous reports as high as 17 percent). They also found declines in the rates of dialysis need and other long-term complications.

When studying the more recent surgeries, researchers also found that open NSS showed some benefits compared with laparoscopic NSS. While laparoscopic NSS can often offer patients reduced postoperative pain, shorter hospital stays and smaller scars, it carries some risks that open NSS actually lessens. For example, Mayo Clinic surgeons needed to clamp the renal artery, stopping blood flow to the kidney, in only 50 percent of open NSS surgeries. For the majority of similarly complex laparoscopic NSS, this artery is clamped for durations typically much longer than those required for open NSS. The importance of limiting artery clamp times was indicated by fewer early surgical complications seen in patients with 20 minutes or less of stopped blood flow.

Dr. Blute's team concluded that open NSS remains the standard by which other treatments should be evaluated. "While there is a definite benefit for many patients with tumors on the kidney's surface to have laparoscopy," says primary author R. Houston Thompson, M.D., "we find that NSS via an open approach remains the best option for patients with complex kidney tumors. In addition, we are now performing open NSS through mini-incisions of less than five inches, which reduces pain and helps with a speedy recovery."

This study reviewed records of all patients undergoing open NSS between 1985 and 2001. The records were obtained from the Mayo Clinic Nephrectomy Registry, which includes over 4,000 patients who underwent either NSS or radical nephrectomies since 1970.