Need for Upper Urinary Tract Stenting in Cases of Ureteral Orifice Injury During Laser Enucleation of the Prostate

Benign prostatic hyperplasia (BPH) is characterized by accelerated growth of glandular tissue in the prostate. In some patients, BPH is associated with a marked intravesical protrusion in which case the ureteral orifices adjacent to the bladder neck may be found in close proximity to the adenoma lobes. Therefore, during prostate surgery (resection, vaporization, enucleation), the ureteral orifices may be located directly at the surgery site leading to injury and subsequent deleterious effects on the upper urinary tract. It should be noted that transurethral prostate and bladder surgery is the leading cause of iatrogenic injury of the ureter and its orifice, with rates up to 2%. The latest American Urological Association (AUA) Guidelines list endoscopic enucleation of the prostate (EEP) as the standard for management of BPH of any size. We thought to evaluate our clinic’s experience to address the necessity of urinary tract stenting in cases of ureteral injury during laser EEP.

While upper urinary tract stenting after injury may be employed to prevent ureteral orifice stenosis, it has several drawbacks, namely a higher risk of infection. Such cases require repeat cystoscopy to remove the stent, further increasing the risk of infection. The majority of patients does not tolerate stenting well and complains of pain and discomfort. Moreover, placement and removal of the ureteral stent for ureteral orifice damage inevitably increases surgery time and hospital stay.

The most frequently used lasers in current endoscopic prostate surgery are GreenLight (commonly used for prostate vaporization), holmium (Ho:YAG), and thulium (Tm:YAG and Tm-fiber) lasers (commonly used for enucleation). GreenLight laser with the wavelength of 532 nm penetrates tissues up to 0.8 mm, while holmium laser (Ho:YAG) with the wavelength of 2100 nm has a penetration depth of 0.4–0.7 mm. Thulium fiber laser (1940 nm) only penetrates tissues up to 0.15 mm due to higher absorption of thulium laser energy by tissues enabling safer and more precise incisions. Such a significant difference in penetration depth leads to a difference in laser-tissue interactions. A number of authors suggest that use of Greenlight technology may necessitate stenting for ureteral orifice injury, due to its deeper tissue penetration. Therefore, patients may require stenting not because of the technique (enucleation, vapo-enucleation, resection, etc.), but because of the energy source. While both holmium and thulium lasers showed a good safety profile, we believe thulium fiber laser to have minimum effect on deeper tissues and pose minimal risk to the integrity of vital anatomical structures due to small penetration depth. Nevertheless, this is the first study to investigate the long-term consequences of ureteral injury with a thulium laser during EEP.

Written by: Dmitry Enikeev, MD., Ph.D., Deputy Director for Science, Institute for Urology and Reproductive health, Sechenov University, Moscow, Russia

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