Date of Decision 09-Sep-2019
Date of Acceptance 09-Sep-2019
Date of Web Publication 23-Dec-2019
Keywords: Complications, large stones, percutaneous nephrolithotomy, tubeless
Hsiao SC, Jou YC, Cheng MC, Shen CH, Lin CT, Chen PC, Lai WH, Chen PY. Safety and efficacy of percutaneous nephrolithotomy in patients with large stones: A retrospective study. Urol Sci 2019;30:272-5
Hsiao SC, Jou YC, Cheng MC, Shen CH, Lin CT, Chen PC, Lai WH, Chen PY. Safety and efficacy of percutaneous nephrolithotomy in patients with large stones: A retrospective study. Urol Sci [serial online] 2019 [cited 2020 Jan 23];30:272-5. Available from: http://www.e-urol-sci.com/text.asp?2019/30/6/272/273873
Percutaneous nephrolithotomy (PCNL) procedure was first reported in 1976 by Fernström and Johansson.[1] They described three patients who were unsuitable for open surgery and had renal stones removed using percutaneous procedure. Wickham and Kollett officially reported the procedure in 1981 and used the term PCNL. PCNL has since become the mainstay of large and complicated upper urinary tract stone removal. Despite newly developed shock wave lithotripsy and retrograde intrarenal surgery, PCNL remains a solid technique used in modern urological practices.[2] Limb and Bellman first reported the use of tubeless PCNL in 1995, and numerous reports have since established the procedure's safety and efficacy.[3],[4] However, several contraindications of tubeless PCNL were reported by Ghani et al. in 2016, including massive bleeding, perforation of collecting system, infected stones, and multiple tracts with large stone burdens (staghorn stones).[5] In March 2001, we started to perform PCNLs without nephrostomy tubes. This tubeless modification has rapidly become a routine procedure in our hospital for percutaneous renal surgery, even in patients with large stone burden. In this study, we retrospectively evaluated patients with large stones to verify the safety and efficacy of tubeless PCNL.
Between January 2011 and June 2016, 425 PCNL procedures with tubeless modification were performed at Chiayi Christian Hospital by the regular urology team. Of the 425 patients, 93 were found to have stone sizes ≥5 cm (categorized as Group 1) while the other 332 were found to have stone sizes <5 cm (Group 2). Eighteen staghorn stones were identified in the patients of Group 1. We retrospectively reviewed the treatment of all patients through their medical charts to evaluate the safety and efficacy of tubeless PCNL in the large-stone group. Ethical approval for this study (No. 2019091) was provided by the IRB of Ditmanson Medical Foundation Chia-Yi Christian Hospital on Nov. 29th 2019.
Surgical technique
In all 425 patients, PCNL was performed under endotracheal tube general anesthesia with a single-stage procedure and a single-access tract. Retrograde insertion of an occluding balloon catheter was performed cystoscopically for retrograde saline infusion to create a more hydronephrotic kidney and to prevent the downward migration of stone fragments into the ureter during surgery. Renal access to the attempted calix was performed with the aid of an ultrasound-guided puncture with an 18-gauge needle while the patient was in a prone position. The access tract was dilated with serial coaxial metal dilators to 26–28 Fr based on stone size and renal anatomy, with an open irrigation system to allow leakage of the irrigation fluid from the working sheath. Only rigid nephroscopy and ureteroscopy examinations were performed. Holmium: yttrium–aluminum–garnet laser was used alone or in combination with a pneumonic lithotripter. Forceps and a suction tube were used to remove stone fragments. The bleeding points were cauterized; then, an antegrade procedure with a 6 or 7 Fr double-J catheter insertion was performed. The wound was then closed with two deep stitches to control subcutaneous bleeding.[6] All PCNL procedures were conducted by a team of experienced endourologists. Before surgery, routine prophylactic intravenous antibiotics were administered after urine analysis, urine culture, and sensitivity testing.
Data on patient age, medical history, stone size and location, stone-free rate, blood transfusions, operating time, and complications were retrospectively reviewed and compared between the two groups. The duration of the operation was defined as the time from the insertion of occlusion balloon catheter to Foley insertion for PCNL. All patients underwent routine postoperative kidney–ureter–bladder (KUB) filming or computerized tomography (CT) scans to check for the presence of residual stones and to confirm the position of the double-J catheter. The stone-free rate was calculated with a residual stone size <0.3 cm as judged by postoperative KUB. Postoperative complications were classified into five grades, according to the Clavien–Dindo guidelines. In this study, we grouped Grades 1–3 as nonsevere complications and Grade 4 and above as severe complications. Transfusions were conducted according to bleeding severity, based on the clinical situation and physician's judgments. Data analysis was performed using SPSS software, Version 21 of the SPSS System for Windows (version 21.0; IBM Corporation, Somers, NY, USA). Numerical variables were compared by an independent-samples t-test. Categorical variables were compared using Chi-square or Fisher's exact test as appropriate. P < 0.05 was deemed statistically significant.
The mean age of the 425 patients was 54.5 ± 11.6 years (range 22–86 years). There was no significant difference between the mean age of Group 1 (53.7 years) and Group 2 (54.7 years). Group 1 consisted of 29 female and 64 male patients, whereas Group 2 had 111 female and 221 male patients. Stone size was measured at the maximum diameter by preoperative imaging (KUB film, intravenous urography, or CT scans). The average stone size was 7.8 and 2.7 cm in Groups 1 and 2, respectively. Moreover, the mean operation time in Group 1 was 93.56, compared to 70.64 min in Group 2. The duration of surgery was significantly longer in Group 1 (P < 0.001) and the stone-free rate lower (P < 0.001), owing to the difference in stone size between the two groups. The stone-free rate in Group 1 was 33.3% (31/93) while that of Group 2 was 82.5% (274/332).
A total of 43 patients suffered from postoperative complications after tubeless PCNL (13 in Group 1 and 30 in Group 2). Of these, 39 patients had Clavien Grade ≤3 complications, including transient obstructive uropathy and urinary tract infection with postoperative fever (8% in Group 1 vs. 7% in Group 2). Four cases with severe Clavien Grade ≥4 complications were identified. The rate of postoperative complications was 14% and 9% in Groups 1 and 2, respectively; the difference between the groups was statistically insignificant. Only 2% of Group 1 patients and 0.6% of Group 2 patients suffered from severe complications (Clavien Grade ≥4). No surgery-related deaths occurred in the patients reviewed in this study.
No significant difference was observed in the duration of hospital stay of the two groups (3.2 ± 1.4 vs. 3.05 ± 1.34 days). Six patients in Group 1 (6.4%) and four patients in Group 2 (1.2%) received a postoperative blood transfusion (P = 0.03). The postoperative sepsis rate was 1% (1/93) in Group 1 and 1.5% (5/332) in Group 2, which represents no statistically significant difference. The demographic data of the two study groups is outlined in [Table 1]. There was no statistically significant difference between the groups regarding the stone parameters investigated, nor the stone locations within the urinary tract.
Table 1: Patient demographics and clinical characteristics
Operative data and postoperative examinations are summarized in [Table 2].
Table 2: Patient intraoperative and postoperative data
Urinary tract stones are frequently encountered in medical practice. Due to improved minimal invasive procedures, the use of open surgery in the management of these stones is declining. Although extracorporeal shock wave lithotripsy (ESWL) and retrograde intrarenal surgery (RIRS) have been used as alternative approaches to the treatment of urinary tract urolithiasis, PCNL remains the gold standard for larger and complex upper urinary tract stones. The outcome in patients with large stones is often less favorable when ESWL and RIRS are performed. For expediting percutaneous tract hemostasis, nephrostomy tubes are inserted during the PCNL procedure to allow proper drainage and adequate routing when a second surgical examination is required. The first report describing the use of tubeless PCNL was published by Bellman et al. in 1997. They concluded that tubeless percutaneously renal surgery is a safe procedure and more beneficial than nephrostomy tube placement in selected patients. The length of hospital stays, requirement of analgesics, achievement of normal activities, and treatment costs are considerably lower with tubeless PCNLs.[7] Several other reports have confirmed the safety and efficacy of the procedure. In a meta-analysis review of the efficacy and safety of tubeless PCNL, Yuan et al. concluded that the procedure is effective and safe in the treatment of renal stones in selected patients and led to shorter hospital stays, lower analgesic requirements, less urine leakage, and other complications. These findings were in agreement with Bellman's report.[8] The safety of the patient is considered to be a higher priority than the efficacy of treatment. Tubeless modifications will only be universally accepted when the safety of the procedure has been established. Treating patients with large and complicated stones was shown to be associated with a lower stone-free rate and higher rates of postoperative fever and blood transfusion.[9] The use of tubeless PCNL in patients with a small stone burden (≤3 cm in diameter) has been advocated based on safety considerations.[9]
The management of single, large, nonstaghorn renal stones has been discussed in the CROES PCNL global study. Xue et al. assessed the CROES data from 1448 solitary nonstaghorn stones and concluded that larger-stone size (especially >4 cm) was associated with higher rates of fever and blood transfusion. In addition, a correlation was identified between stone clearance and a larger size. The stone-free rate was 90% for solitary 2–3 cm stones, compared with 84.1% for stones larger than 4 cm.[10] Despite the morbidity rate of patients with large renal stones, PCNL remains the treatment of choice generally. In our study, nephrostomy tube-free PCNLs were performed in 93 patients, with a stone size of 5 cm or larger. The length of hospital stays, occurrence of sepsis, and overall complication rate were not higher in the larger-stone group. However, longer operation times and a higher blood transfusion rate were noted in this group. Our study suggests that the use of tubeless PCNL for the removal of large stones may lead to a slight increase in morbidity without severe complications. Patients with large stone burdens were not excluded from tubeless PCNL treatment. There are a few limitations and constraints of this study. First, the study's retrospective nature compromised its validity. Second, because tubeless modification is the standard routine procedure for patients undergoing PCNL in our hospital, whereas traditional PCNL has not been performed for over a decade, the differences between complications of tubeless and traditional PCNL in patients with large stones are thus not reported in this study.
Urinary stone analysis is not routinely performed after stone removal in our department. Such an analysis would facilitate the prevention of postoperative urolithiasis recurrence.
Our data suggest that a large stone size (≥5 cm) results in a reasonable and acceptably higher rate of blood transfusion without other major complications. Tubeless PCNL is a safe, reliable procedure for treatment of a stone burden ≥5cm. The optimum treatment modality should be chosen based on the patient and stone characteristics as well as the surgeon's experience and availability of equipment.
We thank Enago – https://www.enago.tw/for their assistance in manuscript editing.
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