Table 4.
Clinical studies focused on flexible and navigable ureteral access sheath (FANS).
| Author | Accrual Year | Country | Study Type | Groups of Comparison | Sample Size |
| Chen et al. [46] | Aug 2021–Jan 2022 | China | prospective | - | 53 |
| Gauhar et al. [47] | Nov 2021–Oct 2022 | Multi-centre | retrospective | FANS 10/12 vs. 12/14 | 35 |
| Zhong et al. [48] | Jun 2016–Jan 2018 | China | retrospective | No | 52 |
| Huang et al. [49] | Feb 2022–Feb 2023 | China | retrospective | Yes | 371 |
| Chen et al. [56] | Jan 2022–Nov 2022 | China | retrospective | FURS with FANS versus miniPCNL | 96 pts FURS with FANS versus 96 miniPCNL |
| Zhang et al. [57] | Aug 2021–Apr 2022 | China | retrospective | FANS vs. UAS | 214 pts (102 FANS versus 112 UAS) |
| Liang et al. [58] | Oct 2021–Nov 2022 | China | retrospective | no | 224 |
| Yu et al. [59] | Jan 2021–Sep 2022 | China | retrospective, matched-pair analysis | FANS vs. UAS | FANS 152/conventional 152 |
| Wang et al. [60] | Jul 2017–Jul 2018 | China | retrospective | vacuum UAS vs. miniPCNL | 28 vs. 56 |
| Gauhar et al. [61] | Sep 2022–Mar 2023 | Multi-centre | retrospective | No | 45 |
| Author | Suction Modality | Laser Modality | Operative Time | Stone Free Rate | Definition of Stone Free Rate |
| Chen et al. [46] | FANS (Zhangjiagang, China) 12/14 Fr female: 36 cm; male: 46 cm (negative pressure: 50–150 cmH2O) |
Ho:YAG 20–40 Hz 0.6–1.2 J | 70.8 (26.9) | 29 (69.8%) | stone volume clearance rate = 1 − (residual stone volume/preoperative stone volume) × 100% |
| Gauhar et al. [47] | FANS Elephant II first or second generation (Zhejiang YiGao Medical Technology Co., Ltd., Hangzhou, China) 10/12 Fr and 12/14 Fr 40 to 55 cm (negative pressure: 0.02 MPa) |
TFL 0.2–0.4 J 200–400 Hz and HP Ho:YAG 0.4 J 40 Hz | 76 vs. 63 min | 94.7% vs. 68.8% | Stone-free status was defined as the absence of a single RF > 2 mm on NCCT. |
| Zhong et al. [48] | Flexible pressure-measuring ureteroscopic sheath 12–14 Fr | Ho:YAG | 34.5 ± 18.3 min | 95.7% at Day 1–2, 100% at one month | Residual stone < 4 mm at KUB X-ray or CT-scan if X-ray was negative |
| Huang et al. [49] | FANS 11/13 or 12/14 Fr | Ho:YAG | 40.3 ± 18.9 min in traditional FURS group, 37.7 ± 20.1 min in suction group | 52 (50.5%) and 81 (78.6%) in traditional FURS and suction group respectively at 1 day, 78 (75.7%) and 97 (94.2%) in traditional FURS and suction group respectively at 30 days | Residual fragments < 3 mm at CT scan |
| Chen et al. [56] | 12/14 Fr, 36 cm for female, 46 cm for males, FANS (Woek, Nanchang, China): negative pressure value to 2–7 Kpa. The irrigation volume was adjusted to a range of 80–200 mL/min. |
Ho:YAG 1.0–1.2 J 15–30 Hz. |
49.3 (11.9), 25–74 versus 50.6 (11.4), 25–71 (p = 0.06) | 85.4% versus 90.6% (0.266) | NCCT showing zero stone fragments |
| Zhang et al. [57] | 12/14 Fr UAS (Shenzhen Kang Yi Bo Technology Development Co., Ltd., Shenzhen, China) 45 for male 35 for female; FANS 12/14 Fr (Zhangjiagang Huamei MedicalEquipment Co., Ltd., Zhangjiagang, China) 45 cm for male 35 cm for female negative pressure was set at −20 to −60 kPa. |
Ho:YAG 0.6–1.2 J 5–20 Hz for fragmentation, and the dusting mode using 0.2–0.6 J 20–30 Hz. |
1 d 86.3% versus 75.0% (p = 0.038); 30 d 91.2% versus 81.3% (p = 0.037) | no residual stone or radiological residue fragment < 2 mm | |
| Liang et al. [58] | FANS 12/14 Fr (Elephant II, Zhejiang YiGao Medical Technology Co., Ltd., Hangzhou, China) | Ho:YAG 1–1.5 J 15–20 Hz. |
69.2 ± 65.2 min | postoperative day 1: 172/224 (76.8%); postoperative day 30: 218/224 (97.3%); | absence of any stones or residual fragments ≤ 2 mm under non-contrast CT |
| Yu et al. [59] | FANS–12/14 Fr; Zhangjiagang, China. Conventional UAS–12/14 Fr; Zhangjiagang, China | Ho:YAG 1.0–1.2 J; 15–30 Hz |
FANS 56.5 ± 13.9/UAS 59.9 ± 16.2 | FANS 116 (76.3%) UAS 11 (7.2%) p < 0.001) at 1 day postoperatively No difference at 1 month |
zero stone fragments at CT scans on 1st day and 1 month after the surgery. |
| Wang et al. [60] | FANS (ClearPetra, Well Lead Medical, China) | Ho:YAG | RIRS 72.4 (21.3), 42–106 miniPCNL 67.4 (25), 44–114 | RIRS 25 (89.3%) miniPCNL 52 (92.9%) | zero fragments on low-dose CT on postoperative day 1. |
| Gauhar et al. [61] | FANS Clearpetra 12/14 Fr | Not mentioned | 65 min | 93.3% at three months | Absence of stone fragments at CT scan |
| Author | Sepsis Rate | Ureteric Injury Rate | Other Complications | Outcome | |
| Chen et al. [46] | 2 (4) | 0 | Emesis: 2 (3.8%) | intelligently pressure-controlled flexible URS in treating upper urinary tract calculi for patients with a solitary kidney with advantages of high lithotripsy efficacy and low complication rate. | |
| Gauhar et al. [47] | 4 vs. 0 | 0 | 1 fornix rupture | treatment of large urinary tract stone > 1.5 cm with system shows shorter operative time, lower incidence of postoperative fever and secondary surgery, and higher stone clearance rate | |
| Zhong et al. [48] | Fever 1/52 | 1 Ureteral extravasation | 8/52 Haematuria without transfusions | Ureteroscopic lithotripsy with intelligent pressure control improves the efficiency of the lithotripsy and rate of stone clearance | |
| Huang et al. [49] | Fever rate: 3.6% vs. 6.3% in traditional FURS and suction groups, respectively. Absence of sepsis | Non-reported | Not reported | vacuum-assisted dedusting lithotripsy (VADL) technique can significantly improve the postoperative SFR for the patients with kidney or proximal ureteral stones less than 3 cm in size treated by flexible ureteroscope. | |
| Chen et al. [56] | infection: 0% versus 3.1%; fever 4.2% versus 7.3% | NR | total complications: 5.2% versus 13.5% (p = 0.048); emesis: 1% versus 4.2%; transfusion: 0% versus 1%; interventional embolization 0% versus 1% | In the treatment of 2–3 cm renal stones, FURS with a novel FANS may provide a superior alternative to mini-PCNL, potentially challenging its established status | |
| Zhang et al. [57] | infectious: 8.8% versus 18.8% (p = 0.037) (fever: 3.9% versus 9.8%) (urosepsis 3.9% versus 6.3%) (septic shock 1% versus 2.7%) | 0 versus 0 | overall complications: 11.8% versus 22.3% (p = 0.041); Hb loss −0.54 +/− 0.69 g/dl versus −0.83 +/− 0.66 g/dl, p = 0.002); steinstrasse: 0% versus 1.8% | Compared to UAS combined with flexible ureteroscope for treating unilateral renal calculi, FANS had superiority in higher SFR on 1 day and 30 days postoperatively. Shorter operation time, lower haemoglobin loss, and lower incidences of overall and infectious CR were observed in FANS group. | |
| Liang et al. [58] | Fever–2/224 | 0 | 0 | for single kidney stone with a diameter of 2–3 cm, intelligent pressure-controlled FURS and MPCNL are both effective treatment methods, but the FURS has advantages, such as fewer complications, shorter hospital stay, and less bleeding. | |
| Yu et al. [59] | FANS 9 (5.9%)/conv UAS 28 (11.9%) | no | no | FANS has a higher SFR 1 day postoperatively. In addition, FANS has contributed to shorter operative time and fewer complications. | |
| Wang et al. [60] | FANS-2. miniPCNL-5 | no | no | In the treatment of 2–4 cm renal stone, using FANS in RIRS can improve surgical efficiency with lower postoperative early pain scores. | |
| Gauhar et al. [61] | Fever 16/45 (35.6%), Sepsis 0/45 | 3/45 (6.7%) | Reintervention for residual fragments 3/45 | FANS improves single-session SFR and reduces the need for a ureteric stent or catheter | |
UAS—(conventional) ureteral access sheath; MPCNL—minimally invasive percutaneous nephrolithotomy; Ho:YAG—Holmium:Yittrium-Aluminium-Garnet; TFL—Thulium Fibre Laser; KUB—X-ray of kidney ureter and bladder; NCCT—non-contrast computer tomography; RF—residual fragment; SFR—stone-free rate.