Technique, Feasibility, Utility, Limitations, and Future Perspectives of a New Technique of Applying Direct In-Scope Suction to Improve Outcomes of Retrograde Intrarenal Surgery for Stones

Abstract

Retrograde intrarenal surgery (RIRS) is accepted as a primary modality for the management of renal stones up to 2 cm. The limitations of RIRS in larger volume stones include limited visualization due to the snow-globe effect and persistence of fragments that cannot be removed. We describe a new, simple, cost-effective modification that can be attached to any flexible ureteroscope which allows simultaneous/alternating suction and aspiration during/after laser lithotripsy using the scope as a conduit to remove the fragments or dust from the pelvicalyceal system called direct in-scope suction (DISS) technique. Between September 2020 and September 2021, 30 patients with kidney stones underwent RIRS with the DISS technique. They were compared with 28 patients who underwent RIRS with a 11Fr/13Fr suction ureteral access sheaths (SUASs) in the same period. RIRS and laser lithotripsy were carried out traditionally with a Holmium laser for the SUAS group or a thulium fiber laser for the DISS group. There was no difference in age, gender, and history of renal lithiasis between the two groups. Ten (40%) patients had multiple stones in the DISS groups, whilst there were no patients with multiple stones in the SUAS group. Median stone size was significantly higher in the DISS group [22.0 (18.0–28.8) vs. 13.0 (11.8–15.0) millimeters, p < 0.001]. Median surgical time was significantly longer in the DISS group [80.0 (60.0–100) minutes] as compared to the SUAS group [47.5 (41.5–60.3) minutes, p < 0.001]. Hospital stay was significantly shorter in the DISS group [1.00 (0.667–1.00) vs. 1.00 (1.00–2.00) days, p = 0.02]. Postoperative complications were minor, and there was no significant difference between the two groups. The incidence of residual fragments did not significantly differ between the two groups [10 (33.3%) in the DISS group vs. 10 (35.7%) in the SUAS group, p = 0.99] but 10 (33.3%) patients required a further RIRS for residual fragments in the DISS group, whilst only one (3.6%) patient in the SUAS group required a subsequent shock wave lithotripsy treatment. Our audit study highlighted that RIRS with DISS technique was feasible with an acceptable rate of retreatment as compared to RIRS with SUAS.

Instrumental dead space and proximal working channel connector design in flexible ureteroscopy: a new concept

“…The findings of the study are of relevance for clinical practice since injection and aspiration through the working channel are frequently performed for various indications during ureteroscopy (Table 3). [11][12][13][14][15][16][17][18][19][20][21][22] An IDS as low as possible is desirable in such situations since the mean intrarenal volume is estimated to range between 3 and 5 ml in non-hydronephrotic human kidneys. 5 Considering this, the IDS of the evaluated flexible ureteroscopes represents 22% to 77% of the intrarenal volume.…”

“…This may also have an impact on the methods of instillation of upper urinary tract carcinoma topical therapy agents 38 with differing volumes needed to overcome the instrument dead space, particularly in periods of worldwide shortage. 41,42 Prior studies have evaluated ureteroscope parameters such as irrigation flow, 29,30 direct in scope suction, 17 intrarenal pressure, 43,44 and dust particle size aspirated. 16,31 How IDS impacts these parameters is of high interest and certainly TherapeuTic advances in urology deserves future evaluation in separate studies.…”

Single use flexible ureteroscopes: a review of current technologies and cost effectiveness analysis

“…Newer su-fURS with inbuilt suction can help with reducing intrarenal pressure and temperature, which in turn could translate into lower infection and sepsis rates [27] (Fig. 1).…”

A novel intrarenal multimodal 2D/3D registration algorithm and preliminary phantom study

“…As a diagnostic and therapeutic tool in the management of upper urinary tract pathologies including nephrolithiasis, retrograde intrarenal surgery (RIRS) has been widely utilized. [1][2][3] In RIRS, the surgeon usually needs to use the ureteroscope to search the calyces successively until the target is located. 4 Novice surgeons are often disoriented and less effective due to the tortuous anatomy of the renal cavity and poor visibility due to microhematuria.…”

“…Its prevalence is increasing over the last two decades and is highly recurrent, with recurrence risks as high as 50% within 10 years. As a diagnostic and therapeutic tool in the management of upper urinary tract pathologies including nephrolithiasis, retrograde intrarenal surgery (RIRS) has been widely utilized 1–3 …”