Endoscopic correction of vesicoureteral reflux (VUR) using a bulking agent was initially described in 1981; O’Donnell and Puri advanced the concept by performing subureteric injections using Teflon paste and coining the term “STING” (subureteric Teflon injection). STING has been the most commonly described technique; however, success rates have been approximately 75%. The concept of ureteral hydrodistention was a significant improvement because it permits direct visual injection into the intraluminal submucosal plane. These modifications led to development of the double hydrodistention implantation technique (double HIT), in which total ureteral tunnel and orifice coaptation is achieved by tandem intramural injections. Although efficacy rates up to 94% have been reported with double HIT, success is known to vary widely among surgeons and techniques ( Table 39.1 ). Successful injection has also been achieved for duplex ureters, those associated with paraureteral diverticula, after failed open or endoscopic surgery, and in patients with bladder dysfunction.
|Causes of Endoscopic Failure||Reasons for Successful Treatment|
|Poor technique: improper injection site(s), low injected volume, endpoint of injection unclear||Improved injection technique (total ureteric tunnel coaptation, intraureteric injection); comprehensive algorithm for needle site(s) of injection|
|Absorption of material: 20% by 2 weeks; ≤40% by 1 year||Combination of flap, hydrostatic, and nipple valve configurations|
|Local bulking agent migration (displacement)||Loss of hydrodistention as an endpoint of injection|
|Associated conditions: bladder dysfunction, complete ureteral duplication, grade V VUR, bilateral VUR||Increased volume of injection: greater volume used for VUR and hydrodistention grades|
|Very superficial implant injection into the mucosa (mound takes on a blue reflection) may result in splitting of the mucosal tissue with implant expulsion upon increased bladder pressure|
After induction of anesthesia, the patient is placed in the dorsal lithotomy position. The ability to rotate the cystoscope over the thighs is important, in order to adequately visualize and inject laterally displaced orifices.
A rigid cystoscope with a distal tip of 9.5 Fr or greater and a minimum 4-Fr working channel is required; an offset lens should be used to permit direct passage of the needle in line with ureter without damaging the needle.
The bladder should be filled to less than half capacity during injection to prevent high tension within the detrusor muscle.
Flush the needle with fluid and prime needle with injectable agent.
Evaluate both ureteral orifices before injecting. Hydrodistention is performed with the tip of the cystoscope placed at the ureteral orifice; a pressured stream is achieved by placing the irrigation bag approximately 1 m above the pubic symphysis on full flow. Hydrodistention is graded according to orifice distensibility ( Fig. 39.1 ) and allows for ongoing visualization of intraluminal injection site as well as assessment of injection progress. The orifice should remain closed after treatment when implantation is performed correctly.