Totally Tubeless Versus Standard Percutaneous Nephrolithotomy for Renal Stones: Analysis of Clinical Outcomes and Cost

Abstract

Purpose:

To evaluate the safety and cost-effectiveness of a totally tubeless percutaneous nephrolithotomy (PCNL) by comparing the clinical outcomes and cost analysis between standard PCNL and totally tubeless PCNL for renal stones.

Patients and Methods:

From June 2012 to September 2013, a total of 121 patients with renal stones who underwent totally tubeless or standard PCNL by two experienced surgeons were retrospectively evaluated by group. According to the surgeon's preference for the nephrostomy tube and/or ureteral stent, the present study was designed to be divided into Group 1 and Group 2. Group 1 was performed by one surgeon (H.J. Cho) who preferred a totally tubeless PCNL and Group 2 was performed by the other surgeon (S.H. Hong) who preferred a standard PCNL. We excluded bilateral renal stones, multiple approach, whole staghorn calculi, and previous renal surgery. Patient and stone characteristics, intraoperative and postoperative parameters, and cost analysis were compared between the two groups.

Results:

There were no significant differences in the patient demographics between groups. Mean stone burden was 501.5±361.1 mm² in Group 1 v 535.2±353.1 mm² in Group 2 (P=0.651). Length of hospital stay (1.72±0.58 v 4.10±1.88 days, P<0.001), postoperative pain scores using a visual analog scale (day 0: P<0.001, day 1: P=0.002), and analgesia requirements (33.2±21.3 v 45.2±19.5 mg, P=0.005) for Group 1 v Group 2 showed significant differences. The stone-free rate was 86.4% v 89.8% in Group 1 and Group 2, respectively (P=0.609). There were no significant differences in overall complications between groups (P=0.213). Mean total medical treatment costs in Groups 1 and 2 were 2398.22±549.1 USD and 2845.70±824.2 USD, respectively (P=0.002).

Conclusions:

Many clinical outcomes in the totally tubeless PCNL showed comparable or better results than standard PCNL. We believe that totally tubeless PCNL is an acceptable, safe, and cost-effective alternative to standard PCNL for the treatment of renal stones.

Introduction

Percutaneous nephrolithotomy (PCNL) is known as a standard surgical treatment of large and complicated renal calculi.¹ The development of surgical technique and instruments has contributed to the modification of PCNLs with a smaller working sheath, nephroscope, and nephrostomy tube or even without a nephrostomy tube or ureteral stent.^2

–7 Totally tubeless PCNL is a recent modification without the nephrostomy tube and ureteral stent and has some potential advantages, including reduced postoperative pain and analgesia requirement without stent-related symptoms, shorter hospitalization and convalescence, and lower cost.^{2,5,6,8
–10} However, totally tubeless PCNL has not been widely accepted due to some limitations.^7,11 Most of the studies on totally tubeless PCNL were designed such that intraoperative procedures were uncomplicated with complete stone clearance and preoperatively selected patients had satisfied strict inclusion criteria.^2,5,6,9,10 Most of the case-controlled and randomized studies performed randomization on the completion of uncomplicated PCNL as decided by the subjective judgment and experience of a single surgeon.^5,6,8,10 We surmised that these study designs had a potential for selection bias. For this reason, our study was designed to be performed as a totally tubeless or standard approach, before the PCNL procedure, by two experienced surgeons who had a different preference for the nephrostomy tube and/or ureteral stent, instead of determination of the insertion of nephrostomy tube and/or ureteral stent at the completion of an uncomplicated PCNL. We compared clinical outcomes and cost analysis between the two groups to identify the safety and cost-effectiveness of totally tubeless PCNL for renal stones.

Patients and Methods

Patient selection and study design

From June 2012 to September 2013, we performed 121 PCNLs for renal stones, including 54 of totally tubeless PCNLs and 67 of standard PCNLs. During this study period, all PCNL procedures were predetermined by two experienced surgeons (H.J. Cho and S.H. Hong) who had different preferences for the placement of a nephrostomy tube and/or ureteral stent. The present study was designed such that Group 1 was performed by one surgeon (H.J. Cho) who preferred a totally tubeless PCNL, and Group 2 was performed by the other surgeon (S.H. Hong) who preferred a standard PCNL. We excluded bilateral renal stones (defined as cases that clinically needed bilateral PCNL), multiple approach (defined as an approach requiring more than two nephroscopy tracts), whole staghorn calculi (defined as stones occupying ≥80% of the renal pelvis and renal caliceal system¹²), and previous urinary tract surgery. Twenty-eight patients were excluded based on these exclusion criteria. Thus, Group 1 and Group 2 had 44 and 49 patients, respectively.

A preoperative radiologic evaluation of the kidneys, ureters, and bladder (KUB) and noncontrast computerized tomography (CT) were performed in all patients. Stone burden was measured by the longitudinal and transverse diameters (mm²) using a preoperative CT scan. The total stone burden was the sum of burdens of all stones found in the preoperative CT scan.^13,14 On the first postoperative day, all patients underwent routine plain radiography to check for residual stone fragments. Selected cases were postoperatively evaluated by a noncontrast CT scan or renal ultrasonography to determine the suspected residual stones, radiolucent stones, or complications. In cases of supracostal approach, the plain chest film was performed to identify a hydro/pneumothorax. We compared patient and stone characteristics between the two groups, including age, sex, body–mass index (BMI), ASA score, history of extracorporeal shock wave lithotripsy (SWL), radiopacity, stone laterality, multiplicity and location of stones, and stone burden (Table 1). The two groups were compared with regard to intraoperative parameters, including mean operative time, approach, puncture site, and postoperative parameters, including change in hemoglobin and serum creatinine values, analgesia requirements, postoperative pain score, transfusion rate, and length of hospital stay.

Table 1.

Patient Demographics and Stone Characteristics

Characteristics	Group 1	Group 2	P-value
Number of patients	44	49
Mean age (years)	53.2±14.9	56.0±13.4	0.339
Sex, male:female (%)	32:12 (72.7:27.3)	34:15 (69.4:30.6)	0.723
Stone laterality			0.087
Left:Right (%)	21:23 (47.7:52.3)	32:17 (65.3:34.7)
BMI (kg/m²)	25.3±2.9	24.9±3.0	0.554
ASA score (%)			0.944
1	16 (36.4)	16 (32.7)
2	25 (56.8)	30 (61.2)
3	3 (6.8)	3 (6.1)
Prior SWL (%)	7 (15.9)	6 (12.2)	0.611
Radiopacity			0.675
Radiopaque stones (%)	39 (88.6)	42 (85.7)
Radiolucent stones (%)	5 (11.4)	7 (14.3)
Multiplicity and position of stones (%)			0.013
Single	31 (70.5)	22 (44.8)
Upper calix	2 (4.5)	2 (4.1)
Middle calyx	5 (11.4)	6 (12.2)
Lower calyx	2 (4.5)	1 (2.0)
Pelvis, UPJ	20 (45.0)	8 (16.3)
Partial staghorn	2 (4.5)	5 (10.2)
Multiple	13 (29.5)	27 (56.2)
Partial staghorn	2 (4.5)	4 (8.1)
Stone burden (longitudinal×transverse diameters, mm²)	501.5±361.1	535.2±353.1	0.651

ASA=American Society of Anesthesiologists; BMI=body–mass index; SWL=shock wave lithotripsy; UPJ=ureteropelvic junction.

The visual analog scale (VAS) pain score (0–10: 0, no pain; 10, worst possible pain) and analgesia requirements were used to evaluate postoperative pain. The VAS score was recorded on postoperative day 0 (at 6 hours after the end of the operation), postoperative day 1, and discharge day. Analgesia requirements were recorded by a chart review of all oral and parenteral or intramuscular medication given while in the hospital stay. All medications were converted to morphine equivalent dosage. Patients were discharged from the hospital when patients were hemodynamically stable and pain was controllable with oral medications.

Re-PCNL, SWL, ureterorenoscopic lithotripsy (URSL), and chemolysis were considered as secondary treatment for the residual renal stones (more than 4 mm), when indicated. All patients were followed up at postoperative 1 week, 1 month, and 3 months. At each visit, plain KUB film, urine analysis, complete blood count, and serum creatinine were routinely checked. We performed noncontrast CT for selected cases such as suspected residual stones, radiolucent stones, and complications.

The results were classified as stone free, clinically insignificant residual fragments (CIRFs), and residual stones (more than 4 mm). CIRFs were considered to be ≤4 mm, nonobstructing, noninfectious, and asymptomatic residual fragments found on postoperative evaluation.¹⁵ Effective PCNL was considered if the patient was stone free (no residual fragments) on the intraoperative visual and fluoroscopic check and the postoperative radiologic evaluation. Effectiveness quotient (EQ) in both groups was calculated by the following formula: (percentage of stone free)/(100+percentage of retreatment+percentage of auxiliary treatment).¹⁶

Medical records and data for this study were retrospectively obtained and reviewed. This study was approved by our Institutional Review Board.

Surgical technique

Our surgical technique has been described previously.^17,18 A standard technique was used for PCNL. Antibiotics were administered prophylactically to all patients. All procedures were performed with the patient under general anesthesia in the prone position with all pressure points padded. After the retrograde ureteral occlusion catheterization, percutaneous renal access was obtained under C-armed fluoroscopy and an 18-gauge needle. Tract dilatation was accomplished using balloon dilators of 24F to 30F. The stone was fragmented using a pneumatic or ultrasonic lithotriptor and removed with various kinds of forceps and retrieval graspers through a rigid 22F to 26F nephroscope. At the end of the procedure, the surgeon conducted a visual and a fluoroscopic check for residual fragments and performed anterograde pyelogram to check ureteral peristalsis and urinary leakage. If there was no significant bleeding and stone-free or CIRF status, in the totally tubeless PCNL group, all instruments were removed and the wound was closed with 3–0 nylon sutures. We did not use any additional method for hemostasis except for manual compression.

In the standard PCNL group, a 20F nephrostomy tube was inserted after the completion of the procedure. The decision to remove the nephrostomy tube was based on standard criteria. The nephrostomy tube was clamped when there was minimal hematuria and stable vital signs after close observation of more than one day. Postoperatively, the nephrostomy tube was removed if there were no evidence of pain, fever, or leakage around the tube after clamping. In patients with Double-J stent, the stent was removed as an outpatient department (OPD) procedure on an average 2 weeks postsurgery.

Calculation of medical costs and statistical analysis

The total medical costs were calculated as the sum of the costs of overall hospitalization, the costs of additional treatment (complication-related treatment), and the costs of secondary treatment (treatment for residual stones). The costs of overall hospitalization included room and board, pharmacy and fluid, laboratory test, radiology test, nursing care charges, anesthesia, operating fee, and surgical supplies. The costs of additional treatment were the costs of readmission for major complication, Double-J catheter insertion costs, and follow-up clinic Double-J catheter removal costs. We included the costs of the secondary treatment in the two groups. Common costs, including preoperative and postoperative OPD visit costs, were not considered in this study. We obtained detailed cost information from the electronic medical records reported by the hospital billing department at our institute. All costs of outpatient and inpatient were applied to the National Health Insurance Service (NHIS). Costs of instruments did not change in this study period.

The outcomes of both groups were compared using the Student's t-tests for continuous variables with normal distributions. A chi-square test or Fisher's exact test was used for the analysis of qualitative data. Data are reported as the mean±the standard deviation. P values <0.05 were regarded as statistically significant. All statistics were performed using SPSS 16.0 software (Chicago, IL).

Results

Patient characteristics and outcomes

The patient demographics and stone characteristics of the groups are summarized in Table 1. The parameters, including age, gender distribution, stone laterality, BMI (kg/m²), ASA score, and history of SWL, were not significantly different between groups. The ASA score in both groups was 1 or 2 in more than 90% of patients (93.2% v 93.9%, P=0.944). Radiopacity of stones was similar in the two groups (P=0.675). Group 2 had more multiple renal stones than Group 1 (29.5% v 56.2%, P=0.013). Mean stone burden of Group 2 was greater compared with Group 1, but not significantly different between groups (501.5±361.1 v 535.2±353.1 mm², P=0.651).

Surgical outcomes and stone-free rates

Intraoperative and postoperative parameters are compared in Table 2. The mean operative time in Group 1 was shorter than Group 2, but there was no statistical significance (61.8±22.4 v 66.5±31.3 min, P=0.407). The infracostal approach was performed more commonly in the two groups (90.9% v 95.9%, P=0.417). The puncture site of both groups was n=4 (4.5%) versus n=2 (4.1%) in the upper calix, n=27 (61.4%) versus n=1 (2.0%) in the middle calix, and n=15 (34.1%) versus n=46 (93.9%) in the lower calix. Postoperative hemoglobin and serum creatinine changes were not significantly different between the groups (P=0.490, P=0.652, respectively). There was a similar transfusion rate in both groups (4.5% v 2.0%, P=0.601). The average length of hospital stay (1.72±0.58 v 4.10±1.88 days, P<0.001), postoperative pain scores using VAS (day 0: P<0.001 and day 1: P=0.002), and analgesia requirements (33.2±21.3 v 45.2±19.5 mg, P=0.005) for the 2 groups showed significant differences. However, at the time of discharge, there was no significant difference in postoperative pain score (0.66±1.03 v 1.06±0.96, P=0.056).

Table 2.

Surgical Outcomes and Stone-Free Rates

Parameters	Group 1	Group 2	P-value
Intraoperative parameters
Operative time (min)	61.8±22.4	66.5±31.3	0.407
Approach			0.417
Supracostal (%)	4 (9.1)	2 (4.1)
Infracostal (%)	40 (90.9)	47 (95.9)
Puncture site			<0.001
Upper calix	2 (4.5)	2 (4.1)
Middle calix	27 (61.4)	1 (2.0)
Lower calix	15 (34.1)	46 (93.9)
Postoperative parameters
Drop in hemoglobin level (g/dL)	1.79±1.18	1.96±1.18	0.490
Change in serum creatinine level (mg/dL)	−0.12±0.29	−0.14±0.25	0.652
Analgesia requirements (morphine equivalent, mg)	33.2±21.3	45.2±19.5	0.005
Postoperative pain score (visual analog scale 0–10)
Day 0	4.43±1.99	6.26±1.51	<0.001
Day 1	2.29±1.97	3.81±2.48	0.002
Discharge day	0.66±1.03	1.06±0.96	0.056
Transfusion rate (%)	2 (4.5)	1 (2.0)	0.601
Length of hospital stay (days)	1.72±0.58	4.10±1.88	<0.001
Stone-free rate (%)	38/44 (86.4)	44/49 (89.8)	0.609
CIRFs (4 or<4 mm)	4/44 (9.1)	4/49 (8.2)
Residual stones (more than 4 mm)	2/44 (4.5)	1/49 (2.0)
SFR of opaque stones at the first postoperative day (%)	34/39 (87.2)	39/42 (92.9)	0.392
SFR of opaque stones at the 3-month follow-up (%)	39/39 (100)	42/42 (100)	–
SFR of lucent stones at the first postoperative day (%)	4/5 (80)	5/7 (71.4)	0.735
SFR of lucent stones at the 3-month follow-up (%)	5/5 (100)	7/7 (100)	–
Additional treatments (%)	2 (4.5)	14 (28.5)	0.002
Intraoperative Double-J catheter insertion	0	11
Postoperative Double-J catheter insertion	1	1
Angioembolization	1	1
Thoracic tube insertion	0	1
Secondary treatments (%)	2 (4.5)	1 (2.0)	0.601
PCNL	0	0
SWL	1	0
URSL	0	1
Chemolysis	1	0
Effectiveness quotient	0.827	0.880

CIRF=clinically insignificant residual fragment; PCNL=percutaneous nephrolithotomy; SFR=stone-free rate; URSL=ureterorenoscopic lithotripsy.

The stone-free rate was 86.4% in Group 1 and 89.8% in Group 2 (P=0.609). The additional treatments, including Double-J stent placement, angioembolization, and chest tube insertion, were administered in 2 patients (4.5%) in Group 1 and 14 patients (28.5%) in Group 2. The number of secondary treatment for the residual stones was 2 (4.5%) in Group 1 and 1 (2.0%) in Group 2, respectively (P=0.601). The EQ for Group 1 and Group 2 was similar (0.827 v 0.880).

Complications

Complications classified by the modified Clavien system are summarized in Table 3. Overall complications of the study period were 7 (15.9%) in Group 1 and 13 (26.3%) in Group 2 (P=0.213).

Table 3.

Complications Classified by Modified Clavien System

Classification of complications	Group 1	Group 2	P-value
Complications, n (%)	7 (15.9)	13 (26.3)	0.213
Modified Clavien classification system
Grade I	4 (9.1)	8 (16.3)
Renal pelvis area urinary leakage	0	3
Postoperatively acute urinary retention	2	0
Delayed hematuria	1	3
UTI	1	2
Grade II	0 (0)	1 (2.0)
Ileus	0	1
Grade IIIa	2 (4.5)	3 (6.1)
Postrenal AKI requiring Double-J stent	1	0
Prolonged urinary leakage requiring Double-J stent	0	1
Hemothorax requiring intervention	0	1
Pseudoaneurysm requiring red angioembolization	1	1
Grade IVb	1 (2.3)	1 (2.0)
Sepsis	1	1

AKI=acute kidney injury; UTI=urinary tract infection.

Four (9.1%) of the 7 (15.9%) postoperative complications in Group 1 were minor (Grade I) and 3 (6.8%) were major. Minor complications (Grade I) included 2 patients with acute urinary retention, 1 prolonged postoperative hematuria (mild bleeding and spontaneous resolution), and 1 urinary tract infection. Major complications (Grade IIIa and Grade IVb) included postrenal acute kidney injury requiring Double-J stent placement in 1 case (solitary kidney), 1 pseudoaneurysm requiring selective angioembolization, and sepsis (Grade IVb) in 1 case.

There were 9 (18.3%) minor complications (Grade I-II) and 4 (8.1%) major complications (Grades IIIa and IVb) in the standard PCNL group. Renal pelvis urinary leakage identified by a postoperative noncontrast CT scan was observed in 3 patients, and delayed hematuria and UTI were observed in 3 and 2 patients, respectively. One case was a paralytic ileus (Grade II) and conservatively managed. Major complications (Grade IIIa and Grade IVb) included prolonged urinary leakage requiring Double-J stent placement in 1 case, hemothorax requiring chest tube insertion in 1 case, pseudoaneurysm requiring selective angioembolization in 1 case, and sepsis (Grade IVb) in 1 case.

Cost analysis

The details of cost for both groups are shown in Table 4. The mean total cost of primary treatment between groups was more expensive for Group 2 than Group 1 (2236.82±176.25 v 2587.11±232.90 USD, respectively, P<0.001). Total additional costs were defined as the sum of complication-related additional cost and secondary treatment cost. We calculated the mean total treatment costs using the mean total cost of primary treatment and total additional costs. Mean total treatment costs in Group 1 and Group 2 were 2380.22±549.19 USD and 2845.70±824.23 USD, respectively (P=0.002). Group 1 was less expensive and saved as much as 465.50 USD per case than Group 2.

Table 4.

Costs Analysis

Cost	Group 1	Group 2	P-value
Mean hospitalization cost (USD)
Room and board	28.72±8.20	63.99±29.40	<0.001
Pharmacy and fluid	350.39±86.66	449.59±91.79	<0.001
Laboratory test	177.59±17.73	233.00±49.73	<0.001
Radiology test	40.19±15.20	49.31±8.78	0.001
Nursing charges	43.31±8.51	56.53±17.69	<0.001
Anesthesia	223.83±22.54	232.95±26.80	0.081
Operating fee	524.86±54.42	588.63±129.50	0.003
Surgical supplies	847.91±85.97	913.07±93.21	0.001
Mean total cost of primary treatment (USD)	2236.82±176.25	2587.11±232.90	<0.001
1. Additional cost (USD)
Double-J catheter removal	98.77	1169.85
Double-J insertion	178.77	178.77
Pseudoaneurysm	2180.75	3798.28
Hemothorax	–	1625.06
Sepsis	2644.44	3683.13
2. Secondary treatment cost (USD)
PCNL	–	–
SWL	596.99	–
URSL	–	2216.22
Chemolysis	609.59	–
Total additional costs (1+2) (USD)	6309.33	12671.32
Mean total treatment costs (USD)	2380.22±549.19	2845.70±824.23	0.002

USD=United States dollars.

Discussion

Technological advancements and technical improvements have contributed to the high stone-free rates and low morbidity in PCNL. Many urologists have attempted to modify the PCNL technique, using a smaller working sheath and nephroscope or avoiding a nephrostomy tube with or without ureteral stent. Traditionally, the placement of a nephrostomy tube after the completion of PCNL has several obvious advantages. The nephrostomy tube provides adequate collecting system drainage, tamponades bleeding of renal tract, prevents urinary extravasation, and may permit future access for second-look procedures. However, the nephrostomy tube may be associated with early postoperative discomfort, prolonged hospital stay, and increased postoperative analgesia requirement.^3,4,19 In 1997, Bellman and associates⁴ first reported the tubeless percutaneous renal surgery in 50 patients. In the study, the nephrostomy was replaced with a Double-J stent. The hospitalization, analgesia requirements, and return to normal activity, as well as cost were significantly less with this technique. They concluded that tubeless percutaneous renal surgery was a safe and effective procedure. After this report, tubeless PCNL gained popularity in many centers. Recently, tubeless PCNL has been increasingly used with extended application, including bilateral renal stone and a solitary kidney.^20,21 However, the tubeless PCNL with an indwelling ureteral stent was associated with stent-related symptoms and signs such as pain, urgency, frequency, dysuria, and hematuria and the need to remove the Double-J stent under cystoscopy at a later time.^19,22 In 2004, Aghamir and colleagues² first reported totally tubeless PCNL in 43 patients. They hypothesized that the ureter can be used as a drain in selected patients. In their study, analgesia requirements and length of hospitalization were less than after standard PCNL. They advocated totally tubeless PCNL as a safe and effective procedure with no significant complications, a shorter hospital stay, and less pain in selected patients. Aghamir and colleagues²³ also reported totally tubeless PCNL in renal anomalies. They concluded that totally tubeless renal surgery for the patients with renal anomalies was a safe and effective procedure with substantial advantages in morbidity and cost-effectiveness, regardless of stone burden. Therefore, totally tubeless PCNL has some potential advantages, including reduced analgesia requirement without stent-related symptoms, shorter hospitalization and convalescence, and lower cost. Although totally tubeless PCNL has been reported as safe and efficacious, it has not been widely accepted for some reasons, including urinary extravasation, obstruction by residual fragments, and the need for secondary PCNL.^7,11 Most studies of totally tubeless PCNL had some limitations owing to the small sample size and selection of patients using strict inclusion and exclusion criteria.^{2,5,6,8
–10} In addition, most of the case-controlled and randomized studies performed randomization at the completion of an uncomplicated PCNL as decided by the subjective judgment and experience of a single surgeon.^5,6,8,10 We considered that these randomizations were not practical and could lead to a selection bias. For these reasons, all our patients were scheduled for totally tubeless or standard PCNL without preoperative selection. In other words, our study was designed to be performed as a totally tubeless or standard approach before the PCNL procedure by two experienced surgeons who had a different preference for the nephrostomy tube and/or ureteral stent, instead of determining the insertion of nephrostomy tube and/or ureteral stent at the end of an uncomplicated PCNL.

Our study represents an additional step toward extending the general applicability of totally tubeless PCNL. We included large renal stone >3 cm, partial staghorn calculi, previous SWL, preoperative urinary tract infection, supracostal approach, intraoperative mild to moderate injury or hemorrhage in pelvicaliceal system not requiring transfusion, renal anomaly-like horseshoe kidney, chronic kidney disease, and single functioning kidney. No significant intraoperative bleeding or serious complications were seen in each group during the study period. Even though it was not statistically significant (61.8±22.4 v 66.5±31.3 min, P=0.407), the mean operative time was longer in Group 2. It was likely due to the extra time spent on insertion of the nephrostomy tube and Double-J stent. In our review, analgesia requirement and postoperative pain scores using VAS and average length of hospital stay decreased significantly in the totally tubeless PCNL group. The difference of the length of hospital stay was highly significant (1.72 v 4.10 days, P<0.001). This difference could be attributed to the removal of the nephrostomy tube in Group 2. The nephrostomy tube was removed if there were no evidence of pain, fever, or leakage around the tube after clamping. Therefore, on discharge day, there was no significant difference in postoperative pain score between the groups (P=0.056).

In the present study, the stone-free rate was not statistically different between groups. EQ of both groups was also similar. Secondary treatments for residual stones in both groups were performed within 3 months after PCNL. In Group 1, we treated one case using the chemolytic drug (sodium bicarbonate) irrigation through a percutaneous nephrostomy catheter because the patient refused surgical treatment and SWL. One case in Group 1 was postoperatively managed by SWL for residual stone fragments and 1 patient in Group 2 was treated with URSL. There were no intraoperative complications and no statistical differences in the postoperative and major complication rate between the two groups. In Group 1, postrenal acute kidney injury occurred in 1 patient with a single kidney. It occurred by CIRF and was resolved by Double-J stent insertion and conservative care. In Group 2, there was a case requiring Double-J stent placement due to prolonged urine leakage and another case requiring chest tube insertion for hemothorax. One patient in each group required selective embolization and transfusion in the management of postoperative pseudoaneurysm. One patient with major sepsis was transfused. With regard to complication results, we observed that the most common complication in both groups was associated with bleeding and ureteral obstruction and complication rates were not significantly different (P=0.213). Consequently, we could not find significant differences of stone-free rate and morbidity between groups and considered that the overall efficacy and safety of the totally tubeless PCNL was acceptable, as evidenced by a comparable stone-free rate, secondary treatment rate, and complication rate.

In the Korean insurance system, all patients are registered with the NHIS and NHIS covers a certain portion of the total medical expenditure. The details of costs were converted into U.S. dollars using the mean exchange rate during the study period. We excluded preoperative and postoperative OPD visit cost in the cost analysis, since we were not able to accurately assess the total medical costs for such reason as the cost differences between patients referred from other clinics and patients first visiting our institution and some cases of follow-up loss. We classified total hospital costs as eight items. There were significant differences in the details of total hospital costs except for anesthesia. We considered that these differences reflected the decreased length of stay in Group 1. The significant differences of operating fee and surgical supplies were considered to be due to the nephrostomy tube placement and Double-J stent insertion. In this study, we observed that the mean total cost of primary treatment for renal stones and mean total treatment costs showed statistical differences (P<0.001, P=0.002, respectively). In Group 2, the surgeon preferred to insert the Double-J stent after completion of the procedure when the ureteropelvic junction or upper ureter was inflamed and edematous or residual stone was checked. Operating fee and surgical supplies cost included intraoperative Double-J insertion cost, and Double-J removal cost was applied to the costs of additional treatment. Totally tubeless PCNL reduced the additional intraoperative and postoperative costs and discomfort associated with removal of the stent. With comparable results in the stone-free rate, secondary treatment rate, and complication rate between two groups and better results, including decreased postoperative pain and analgesia requirements, shortened length of hospital stay, and lower costs in the totally tubeless PCNL group, we considered totally tubeless PCNL as a cost-effective technique with low morbidity. We therefore recommend totally tubeless PCNL, if possible, and insertion of the nephrostomy tube or ureteral stent, if indicated.

This study had some limitations. The first limitation of our study was its retrospective nature and low patient population. However, we recorded all data in detail during the study period and our sample size was similar to those in previously reported studies. Second, our data reflected regional cost and may not be applicable to other regions of the world. Third, our PCNLs were performed by two different surgeons. However, the two surgeons had many experiences and comparable skills to each other and had already overcome their initial learning curve. The last limitation of this study was that all patients were not evaluated postoperatively by noncontrast CT scan but were routinely followed by plain (KUB) radiography, which may have overestimated the stone-free rate. However, the noncontrast CT scan was performed to assess the suspected residual stones and radiolucent stones.

Despite these limitations, our study was the first attempt to be performed with predetermined different PCNL approaches from the beginning, with an assessment of the cost analysis of totally tubeless PCNL. We believe that totally tubeless PCNL makes the procedure inexpensive and safe in the patient, with minimal exclusion criteria.

Conclusions

In this study, the totally tubeless PCNL group had a significantly decreased analgesia requirement, postoperative pain score and length of hospital stay, comparable stone-free rate, and more than $465 in cost savings without an increase in the complication rate compared with patients who underwent the standard PCNL. Our findings corroborated previously reported studies. We believe that totally tubeless PCNL is an acceptable, safe, and cost-effective procedure for selected renal stones, and patients undergoing uneventful PCNL procedures are not necessary required to have the nephrostomy tube and/or ureteral stent.

Footnotes

Disclosure Statement

No competing financial interests exist.

Abbreviations Used

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