The search for the definition, etiology, and effective diagnosis of upper urinary tract obstruction: the Whitaker test then and now.
INTRODUCTION
Robert Whitaker, inspired by Dr William W Scott at the Brady Institute at Johns Hopkins and by Sir David Innes Williams at Great Ormond Street Hospital for Children in the late 1960s, spent much of his career exploring the meaning of persistent dilatation of the upper urinary tract, in an attempt to define obstruction and to find a means of diagnosing it accurately.


OBJECTIVE
This is a historical review of Bob Whitaker's journey from his definition of obstruction to the inception of his eponymous test.


RESULTS
In 1975, he proposed a theory to explain the pathophysiology behind obstructive hydronephrosis and megaureter. He was among the first pediatric urologists to observe that 'it is wrong… to assume that dilatation necessarily indicates obstruction', a statement that was widely stated and even appeared in the textbooks at the time. He defined obstruction as 'an increased pressure in the pelvicalyceal system of the kidney at normal physiological flow rates such that the renal function is adversely affected'. This realization led to the development of a percutaneous pressure-measuring technique at controlled flows, later referred to as the Whitaker test. It predated and later assisted in the interpretation of diuretic renograms.


DISCUSSION
Whitaker questioned the etiology of 'hydronephrosis' and challenged other hypotheses proposed at the time, which often included causes of mechanical occlusion at the ureteropelvic junction (UPJ) or ureterovesical junction (UVJ). Whitaker's hypothesis is that 'obstruction' at UPJ and UVJ levels is not mechanical but the result of a failure of normal peristalsis to form and propagate a bolus. This, in turn, depends on the potentially abnormal distensibility of the renal pelvic and ureteric wall whether it be congenital or acquired. The aim of this review is to recall the history of the development of a technique to evaluate dilated upper urinary tracts and to re-evaluate various theories that might explain the etiology of the dilatation in the light of more recent evidence. Robert (or Bob, to his colleagues) Whitaker was among the founder members of the British Association of Paediatric Urologists, which now has more than 50 members, in 1992. Together with his colleagues Philip Ransley and David Thomas, Whitaker established the annual pediatric urology course for pediatric surgery and urology trainees in Cambridge, U.K., which still runs to this day. He retired from his surgical practice in 1990 and up until the present time has taught clinical anatomy in the Cambridge University School of Medicine.