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ORIGINAL ARTICLES |
Key Words: Vesico-Ureteral Reflux, Ureteral Reimplantation, Obstruction, Renal Function
Corresponding Author:
Mark P. Cain, MD
Department of Urology
JW Riley Hospital for Children
702 Barnhill Drive #1739
Indianapolis, Indiana 46202
(317) 274-7446
Fax: (317) 274-7481
email: mpcain@iupui.edu
Objectives: To evaluate the effect of unilateral ureteral
reimplantation on ipsilateral renal function, specifically to demonstrate whether
a postoperative renal scan is necessary following ureteral reimplantation.
Methods: We reviewed all children that underwent unilateral ureteral reimplantation
that fit the following criteria: i) renal scan performed preoperatively and following
surgery, ii) a normal contralateral kidney, iii) no other bladder or renal pathology.
Results: 33 patients were identified that met the inclusion criteria. The
Cohen technique was used in 26 patients, Leadbetter-Politano in 5, and extravesical
approach in 2. Postoperative renal scans demonstrated a mild decrease in differential
function in 21/33 patients (64%). Only 3/33 (9%) had a decrease in function of 5%
or greater (average 5.3%), which is the accepted error for nuclear renal scans.
Conclusion: This study demonstrates that relative renal function is only mildly
impaired in the majority of patients following ureteral reimplantation. This data
would support omitting a postoperative functional study following uncomplicated ureteral
reimplantation.
In some cases, ureteral reimplantation can result in significant transient postoperative renal obstruction with subsequent renal impairment in the early postoperative period. Early ureterovesical junction obstruction is a recognized complication of ureteral reimplantation (1-3). To date no study has demonstrated whether transient unilateral postoperative obstruction affects ipsilateral renal function using early postoperative nuclear renal scans. In order to determine if there is a significant decrease in renal function following reimplantation surgery, we evaluated patients that had undergone unilateral ureteral reimplantation that had a normal contralateral kidney to serve as an internal control.
We retrospectively reviewed the medical records, operative reports,
and renal scans of all patients that underwent unilateral ureteral reimplantation
over the past five years. Criteria for inclusion in the study included unilateral
reflux treated surgically; a normal contralateral kidney; no previous history of
ureteral or bladder surgery; and a MAG-3 or DTPA renal scan performed both pre-operatively
and post-operatively. Patients with associated ureteroceles or large periureteral
bladder diverticula were excluded. No ureteral stents were used , and urethral catheters
were removed on post-op day two or three. Postoperative pain was managed with intrathecal
narcotics, anticholinergics and oral narcotics as needed.
A significant change in differential function was defined as >5% for the purposes
of this study. This value represents the accepted variability for nuclear scans.
Between 1994 and 1998, 33 patients met the inclusion criteria. This included 29 females and 4 males, with an average age of 5.6 years (range 8 months-12 years) at the time of surgery. The grade of reflux pre-operatively was Grade II in 7 patients, grade III in 16 patients and grade IV in 10 patients. Reflux occurred on the left side in 22 patients and the right in 11 patients. All had a normal contralateral kidney based on a renal ultrasound and preoperative renal scan. The reflux was surgically corrected with a unilateral reimplantation in all patients. The Cohen technique was used in 26 patients (79%), a Leadbetter-Politano procedure in 5 patients (15%), and an extravesical approach in 2 patients (6%). A post-operative VCUG at 4 to 6 months demonstrated resolution of the reflux in all patients. Post-operative renal scans revealed decreased differential function on the operated side in 21/33 patients (64%), increased renal function in 11/33 (33%), and no change in renal function in 1/33 patients (3%). All patients had good drainage without evidence of obstruction. Of the patients with a decrease in their renal function, only 3/33 (9%) had a significant change based on the standard error of 5% used as the accepted variability for renal scans. The mean change among these three patients was 5.3%, individual values showing a change in differential function of 5% ,5% and 6%. Interestingly, all three patients with significantly decreased function had common sheath reimplants for duplicated ureters using the Cohen technique. Three of ten patients (30) that underwent common sheath reimplants had significant decreased ipsilateral renal function on postoperative scans. All patients had normal renal ultrasounds at three months following surgery.
Early in the postoperative period it has been shown that patients
can experience varying degrees of obstruction at the ureterovesical junction. This
is thought to occur because of the contributions of edema, subtrigonal bleeding and
bladder spasms that are experienced post-operatively. This obstruction has been shown
to be transient and appears to resolve spontaneously in a majority of cases (3),
but would most likely result in at least temporary decreased renal blood flow and
glomerular filtration rate with elevated ureteral pressures as seen in other models
of ureteral obstruction (4).
Studies to this point have focused on the recognition and diagnosis of post-operative
obstruction (5), and the long term effect surgical correction of reflux has on renal
function (6-11). It has not been investigated, however, whether transient obstruction
leads to a significant decrease in differential renal function of the involved kidney
following unilateral ureteral reimplantation, where the contralateral normal kidney
can serve as an internal control with respect to differential function postoperatively.
The present study reveals that renal function is not significantly effected in the
early postoperative period. Although 64% of the patients that underwent unilateral
ureteral reimplantation had a minor decrease in differential function, the change
in renal function was found to be significant in only 3 of the 33 patients studied.
These patients all had a small change in renal function of </= 6%, followed by
normal renal ultrasounds in later follow-up. These findings led us to conclude that
changes in renal function following ureteral reimplantation are insignificant and
minor.
Unilateral ureteral reimplantation is not associated with a significant decrease in ipsilateral differential renal function on postoperative renal scans. We found that 64% of patients who underwent unilateral reimplantation had a clinically insignificant decrease in renal function post-operatively, with only 9% of patients showing a notable change. No kidney suffered a reduction in function greater that 6%. This data demonstrates that changes in differential renal function following ureteral reimplantation are usually minor, and would support omitting postoperative functional studies following uncomplicated ureteral reimplantation.
