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ORIGINAL
Efficacy of the direct grasping technique using pean forceps
under fluoroscopy to replace ureteral stents in women
Yutaro Sasaki1, Masayuki Takahashi1, Keisuke Ozaki1, Kei Daizumoto1, Yoshiteru Ueno1, Megumi Tsuda1,Yoshito Kusuhara1, Tomoya Fukawa1, Yasuyo Yamamoto1, Kunihisa Yamaguchi1, and Hiroomi Kanayama1
Department of Urology, Tokushima University Graduate School of Biomedical Sciences, Tokushima, Japan1

Abstract : Purpose : To evaluate the efficacy of the direct grasping technique using pean forceps under fluoroscopic guidance for ureteral stent replacement in women. Methods : Between April 2018 and September 2020,
28 female patients underwent ureteral stent replacements at our facility, and 184 stent replacement procedures
were performed. A total of 127 stents were replaced using pean forceps under fluoroscopic guidance (pean forceps group), and 57 stents were replaced using the cystoscope (cystoscopy group). Clinical characteristics andsurgical outcomes were compared between the groups. Results : All stents were successfully replaced. There wasa statistically significant difference in the procedure time between the two groups (median [interquartile range],pean forceps group : 10.8 [8.2–13.9] minutes vs. cystoscopy group : 15.8 [11.1–20.9] minutes, P < 0.001). There were
no intraoperative complications in either group and no difference in the incidence of postoperative complications (pean forceps group : 1.6% vs. cystoscopy group : 1.8%, P = 1.000). Fluoroscopy time was longer in the peanforceps group, although this difference was not statistically significant (pean forceps group : 38.9 [22.6–60.1] seconds vs. cystoscopy group : 33.0 [20.0–48.9] seconds, P = 0.0558). Conclusion : The direct grasping technique usingpean forceps under fluoroscopy may be a beneficial alternative to cystoscopy for ureteral stent replacement inwomen. J. Med. Invest. 68 : 326-329, August, 2021
Keywords : ureteral stent replacement, pean forceps, fluoroscopy

INTRODUCTION
Ureteral stents are small tubes inserted into the ureter totreat or prevent a blockage that impedes the flow of urine fromthe kidney to the bladder. Usually within several months after
the first placement, these stents must be removed or replaced
to avoid complications such as migration, encrustation, further obstruction, or infection (1). Several methods are used toreplace ureteral stents. The conventional method, cystoscopy,
involves passing a rigid tube (with a lens and camera at the end)
through the urethral sheath, thus painful or uncomfortable forthe patient. Cystoscopy is frequently performed using a tube
with a large diameter (from 18-Fr to 22-Fr) (2). To overcome theshortcomings of these stent replacement methods, we devised adirect grasping technique using pean forceps under fluoroscopic
guidance. Pean forceps are inexpensive, widely available, andthinner than a cystoscope. In this study, we compared the efficacy of cystoscopy with that of the direct grasping techniqueusing pean forceps under fluoroscopic guidance for ureteral stent
replacement in women.

PATIENTS AND METHODS
Study population and design

For this retrospective cohort study, we reviewed the archivesof Tokushima University Graduate School of Biomedical Sciences for ureteral stent replacements performed from April 2018 toReceived for publication May 12, 2021 ; accepted July 13, 2021.
Address correspondence and reprint requests to Yutaro Sasaki, M.D.,
Department of Urology, Tokushima University Graduate School of Biomedical Sciences, 3-18-15, Kuramoto, Tokushima, 770-8503, Japan.

September 2020. These procedures were categorized according
to the surgical technique employed : either cystoscopy or direct
grasping using pean forceps under fluoroscopic guidance. All
women who underwent stent replacement at our facility sinceApril 2018 to September 2020 were eligible. Patients who underwent another procedure simultaneously were excluded. Allprocedures were performed by eight urologists. Patient medical
history and anthropometrics were assessed along with thefollowing factors : stent replacement outcome, procedure andfluoroscopy times. The institutional review board approved
this study (protocol number 4063), and all patients provided
informed consent.

Collection of demographic and clinical data from the medicalarchive
Data collection was performed between April 1, 2018 and September 30, 2020. As indicated in the archive, all procedures wereperformed in a fluoroscopic room within the hospital. For stent
replacement using pean forceps under fluoroscopic guidance,
the general procedure was as follows : the patient was placedin a lithotomy position without anesthesia. Pean forceps (Fig.
1. a) were sterilized by autoclaving. Lidocaine jelly was applied
to the forceps, which were gently inserted through the urethra.
To guide the path of the forceps, fluoroscopy was used. This imaging technique uses X-rays to obtain real-time moving imagesof the patient’s organs. Under fluoroscopic guidance (Fig. 1. b),
the surgeon used the forceps to grasp and remove the distal endof ureteral stent through urethra to external urethral meatus.
The surgeon then inserted a guide wire through the ureteralstent to the renal pelvis or intra pelvicalyceal system, took out
the old ureteral stent over the guide wire, slid the new stent overthe guide wire, and took out the guide wire at external meatuslevel while gently sliding the distal end of ureteral stent over theguide wire into the urethra. The fluoroscopic apparatus used
was the DynaDirect Winscope 6000 (Toshiba Medical Systems,

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The Journal of Medical Investigation Vol. 68 August 2021

327

Figure 1.

a. Pean forceps.
b. Fluoroscopic image showing pean forceps successfully grasping the stent.

Tochigi, Japan). For stent replacement using cystoscopy, thegeneral procedure was as follows : a 22-Fr rigid cystoscope wasinserted through the urethra. Using grasping forceps, the stent
was removed under direct view. The surgeon then inserted areplacement stent under fluoroscopic guidance.

Statistical analysis
All continuous variables are expressed as the median (interquartile range). While performing our analyses, the t-test wasused for continuous variables, and Fisher’s exact test was usedfor nominal variables. A p-value < 0.05 was considered statistically significant. The EZR (Easy R) version 1.32 was used forstatistical analysis (3).

was no difference in the incidence of postoperative complications
between the groups (pean forceps group : 1.6% vs. cystoscopy
group : 1.8%, P = 1.000). All complications were low-grade urinary tract infections. Three patients experienced a urinary
tract infection within 1 week after stent replacement, but thiscomplication resolved after several days of antibiotic infusion
therapy. The median procedure time was significantly shorter inTable 1. Clinical characteristics of female patients who underwent
a replacement of ureteral stents
Age, years, median (IQR)

62 (56-73)

BMI, kg / m2, median (IQR)

20.6 (19.0-21.8)

Etiology, number of patients (%)

RESULTS

Gynecologic cancer

15 (53.6)

Patient characteristics

Gastrointestinal cancer

10 (35.7)

During the retrospective study period, 28 female patients underwent stent replacement procedures at our institution. Theiranthropometric and clinical characteristics are summarizedin Table 1. Their median age was 62 years, and their median
BMI was 20.6 kg / m2. The etiology of ureteral obstruction was
gynecologic cancer in 15 patients, gastrointestinal cancer in 10
patients, benign disease in 2 patients, and urinary cancer in 1
patient. Six patients (21.4 %) had bilateral stent replacements.

Benign desease

2 (7.1)

Urinary cancer

1 (3.6)

Side, number of patients (%)
Right

11 (39.3)

Left

11 (39.3)

Bilateral

6 (21.4)

Stent type, number of stents (%)

Technique outcomes : direct grasping technique using pean forceps
under fluoroscopic guidance versus cystoscopy

Double pigtail configuration

33 (97.1)

Loop configuration

1 (2.9)Among the 28 patients in our study, 184 ureteral stent replacements were performed. Of these, 127 stents were replacedusing pean forceps under fluoroscopic guidance (the pean forcepsgroup), and 57 stents were replaced using cystoscopy (the cystoscopy group). Almost all stents were double pigtail stents. In
the pean forceps group, all stents were successfully replaced.
In the cystoscopy group, all stents were replaced successfully.
The surgical outcomes are shown in Table 2. There were no
intraoperative complications in either group. Similarly, there

Stent length (cm), number of stents (%)
225 (14.7)

2420 (58.8)

269 (26.5)

Stent diameter (Fr), number of stents (%)
633 (97.1)

71 (2.9)

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Y. Sasaki, et al. Ureteral stent replacement in women

Table 2. Surgical outcome in female patients who underwent a replacement of ureteral stents
Overall

Pean forceps

Cystoscopy(n = 184)(n = 127)(n = 57)

12.0 (8.7-16.0)

10.8 (8.2-13.9)

15.8 (11.1-20.9)

Right

63 (34.2)

39 (30.7)

24 (42.1)

Left

45 (24.5)

26 (20.5)

19 (33.3)

Bilateral

76 (41.3)

62 (48.8)

14 (24.6)

175 (95.1)

122 (96.1)

53 (93.0)

Loop configuration

9 (4.9)5 (3.9)4 (7.0)

Success of replacement

184 (100.0)

127 (100.0)

57 (100.0)

Active bleeding

0 (0.0)0 (0.0)0 (0.0)Urinary tract infection

3 (1.6)2 (1.6)

1 (1.8)1.000

34.0 (20.9-54.1)

38.9 (22.6-60.1)

33.0 (20.0-48.9)

0.0558Procedure time (min), median (IQR)

p value< 0.001

Side, number of stents (%)
0.00597

Stent type, number of stents (%)
Double pigtail configuration

0.462

Complications

Fluoroscopy time (sec), median (IQR)

the pean forceps group (10.8 [8.2–13.9] minutes) than in the cystoscopy group (15.8 [11.1–20.9] minutes, P < 0.001). The fluoroscopy time was longer in the pean forceps group (38.9 [22.6–60.1]
seconds) than in the cystoscopy group (33.0 [20.0–48.9] seconds,
P = 0.0558). Eleven patients underwent multiple ureteral stent
replacements at both the technique using pean forceps andusing cystoscopy. Figure 2 shows the median procedure time foreach technique in 11 patients. The procedure time was reduced
by 38.2 % in 9 patients (81.8 %).

Figure 2. The median procedure time for each technique in 11
female patients.

DISCUSSION
Ureteral stents are small tubes inserted into the ureter totreat or prevent an obstruction that impedes the flow of urine
from the kidney to the bladder. Ureteral obstructions may becaused by various conditions, including tumors and kidneystones. To prevent complications such as encrustation andinfection, ureteral stents must be removed or replaced withinfour to six months of insertion (1). Ureteral stent replacement is

a minimally invasive surgical procedure commonly performedby urologists. Cystoscopy, a widely used method for replacing
ureteral stents, involves passing a rigid or flexible tube (with alens and camera at the end) through the urethral sheath, which
may be painful for the patient. To address this problem, otherstent replacement methods have been reported (2, 4-6). These
include the guidewire lasso technique, the snare technique,the crochet hook technique, and the cystoscopic direct graspingtechnique. The guidewire lasso technique involves inserting afolded guidewire through the urethral sheath to make a lasso.
Using this lasso, the ureteral stent is removed under fluoroscopicguidance. The snare technique uses a gooseneck snare insteadof a folded guidewire. The guidewire lasso and gooseneck snaretechniques require extra equipment and are difficult to perform,so fluoroscopy time is inevitably long. Gadzhiev et al. reported
that the snare technique, under ultrasound guidance, also
requires practice and special skills (5). The cystoscopic direct
grasping technique uses forceps located inside the cystoscope.
The cystoscopic camera uses x-ray imaging, so fluoroscopy is notneeded. The crochet hook technique uses neither cystoscope nor
fluoroscopy : a metal crochet hook is inserted into the urethra(usually five to ten times) until the ureteral stent is grasped andremoved. The success rate for this technique is 83.9% (6). Whenit fails, the procedure is repeated under fluoroscopic guidance
and takes additional time to accomplish.
Although some urologists insist that forceps may damage thebladder mucosa, the patients in our study did not suffer from any
injury. Our results thus indicate that our newly devised method
could be performed safely. One advantage of this method is theelimination of the need to prepare for a cystoscopy and clean up
the fluoroscopy room, which reduces the occupation time in thefluoroscopy room relative to methods based on cystoscopy. Therefore, we can perform stent exchanges more rapidly and in morepatients. Another advantage of this method is that the patient’s
pain or discomfort is reduced because a pean forceps is thinnerthan a cystoscope. Moreover, this method does not require theclinician to consider an increase in intravesical pressure causedby saline instillation or poor visibility due to cloudy urine.
It is left to the discretion of the surgeon whether to use pean
forceps or cystoscopy. In April 2019, one urologist (Y.S.) introduced the method using pean forceps at our facility. After that,

The Journal of Medical Investigation Vol. 68 August 2021
the method using pean forceps became widespread rapidly.
Therefore, the majority of patients in the cystoscopy group
underwent stent replacement during the first half of the study
period, while most patients in the pean forceps group were included in the second half. Fluoroscopy was used to remove thestent when using pean forceps. Therefore, the radiation exposure
increased and affected the fluoroscopy time. To reduce radiation
exposure, it would be useful to investigate the efficacy of stentreplacement using pean forceps under ultrasonic guidance.
This study had limitations. It was a single-center, retrospective study. The sample size was small, and all patients werefemale. The fluoroscopy equipment at our facility could not measure the dose area product (i. e., the total amount of radiationdelivered to the patient) nor the air kerma (i. e., the dose of radiation delivered to a specific point on the patient’s body).

ACKNOWLEDGEMENT
The authors thank the patients who participated in this study,
as well as their families and caregivers, investigators, and site
personnel involved.

REFERENCES
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CONCLUSION
Our results suggest that in women, ureteral stent replacement
may be safely performed using the direct grasping techniquewith pean forceps under fluoroscopic guidance. This method may
be a useful alternative to conventional cystoscopy. The efficacy
and safety of this technique merits further evaluation.

4.

5.

CONFLICT OF INTEREST
The authors report no conflict of interest.

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