"Dusting" Versus "Basketing" - Treatment Of Intrarenal Stones

To date, there is inadequate literature to confidently determine the ideal technique of stone extraction during ureteroscopy, an endourologic procedure for the treatment of kidney stones. The goals of ureteroscopy for intrarenal stones are to fragment stones and minimize residual fragments while doing so in a safe and expeditious way with minimal harm to the patient. Options for the treatment of intrarenal stones consist of using a basket to pull them out or a laser to break them into small fragments. When stones are deemed too large to be basketed primarily, the standard preference in ureteroscopic laser lithotripsy is use of the Holmium:YAG laser which can effectively break stones into fragments small enough to remove or pass spontaneously.

There is no consensus on how to achieve optimal stone clearance once the primary stone is fragmented with lithotripsy. Many urologists choose to "dust" the stone by breaking it into tiny fragments < 1 - 2 mm in size with the assumption that stone fragments of such a small size will pass spontaneously after surgery. This can theoretically decrease operative times and lower risk of ureteral trauma by minimizing repetitive introduction and removal of the ureteroscope. Others choose to actively extract each possible stone fragment during the procedure thereby increasing the immediate stone-free outcome.

Active extraction however typically increases costs as it requires use of a basket or grasper and ureteral access sheath. To date, only one prospective, randomized study has addressed the practice of active extraction vs spontaneous passage, the results of which suggested higher rates of residual stone fragments, hospital readmissions and need for ancillary procedures when stones were not actively extracted (8). This study was criticized for not following a standardized operative protocol and not reporting several important outcomes including stone composition. Additionally, this study used semirigid ureteroscopy, specifically addressed ureteral rather than intrarenal stones, and did not follow a "dusting" protocol assuring minimal size of residual fragments.

Complete eradication of stone fragments is one of the primary outcomes of ureteroscopy as residual renal stone fragments after ureteroscopy have been shown to lead to a subsequent stone event in approximately 20% of cases(9). However, maximizing eradication of stone fragments must not come at the expense of the patient. For this reason it is important to consider the operative variables associated with the different techniques employed to clear stone during such procedures.

For example, an average of nearly three times as much laser energy was used to fragment the stone into tiny pieces compared to active extraction (8). Conversely, active extraction of stone fragments requires introducing and removing the ureteroscope through the ureter a greater number of times in order to facilitate stone removal; which generally requires use of a ureteral access sheath, a treatment with its own associated risk.(10). The short term and long term differences resulting from use of these techniques is currently unknown.

Inclusion criteria

• Radiopaque renal stones above the level of the ureteropelvic junction
• Kidney stones must range up to 20 mm in size or in the case of multiple stones the conglomerate diameter (additive maximal diameter of all stones on axial imaging of computed tomography) up to 20 mm is required for inclusion
• Patient must be a suitable operative candidate for flexible ureteroscopy

Exclusion criteria

• Patients who have had prior ipsilateral upper urinary tract reconstructive procedures or history of ipsilateral ureteral stricture
• Patients who have undergone prior radiotherapy to the abdomen or pelvis and those who have a neurogenic bladder or spinal cord injury
• Pregnant subjects