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Table of Contents
ORIGINAL ARTICLE
Year : 2020  |  Volume : 31  |  Issue : 6  |  Page : 273-276

Comparison of stone-free rate, operation procedure, and complication rate according to guy's stone score in supine percutaneous nephrolithotomy


1 Department of Urology, Gunung Jati General Hospital, Cirebon, West Java, Indonesia
2 Department of Urology, Faculty of Medicine Universitas Padjadjaran, Dr. Hasan Sadikin General Hospital, Bandung, Indonesia

Date of Submission27-Jun-2020
Date of Decision08-Sep-2020
Date of Acceptance08-Oct-2020
Date of Web Publication26-Dec-2020

Correspondence Address:
Yulfitro Manurung
Department of Urology, Faculty of Medicine Universitas Padjadjaran, Dr. Hasan Sadikin General Hospital, Bandung
Indonesia
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/UROS.UROS_94_20

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  Abstract 


Background and Aim: Percutaneous nephrolithotomy (PCNL) was considered a safe and efficient method for removing kidney stones, with a low incidence of complications. This study aims to compare the success rate of PCNL based on guy's stone score (GSS) operating procedure and its complications. Methods: Data were collected from patients with kidney stones who underwent PCNL. A stone-free rate (SFR) was considered if the patient was either had no stone or had any stone that is <4 mm and asymptomatic residual fragment. Complications were assessed using the modified Clavien score, and SFR was assessed by abdominal radiography. Results: A total of 198 patients were included in this study. There was a significant difference in SFR between simple (GSS I and II) and complex stone (GSS III and IV) groups (P = 0.000). The operation procedure was longer in the complex group compared to the simple groups for both total operating time and stone fragmentation time (P = 0.000). X-ray time was not significantly different (P = 0.061). Almost all patients were classified as Clavien I, as there was no significant difference between the two groups for complication (P = 0.277) or blood loss (P = 0.176). Conclusion: The success rate of PCNL based on the GSS at Gunung Jati Regional Hospital is quite good. There was a difference in the SFR between the groups, and the operating procedure time was longer in the complex stone group. There was no difference between the simple stone and complex stone groups in PCNL complications, which indicated a good surgical practice.

Keywords: Guy's stone score, modified Clavien score, percutaneous nephrolithotomy


How to cite this article:
Ferdian V, Manurung Y. Comparison of stone-free rate, operation procedure, and complication rate according to guy's stone score in supine percutaneous nephrolithotomy. Urol Sci 2020;31:273-6

How to cite this URL:
Ferdian V, Manurung Y. Comparison of stone-free rate, operation procedure, and complication rate according to guy's stone score in supine percutaneous nephrolithotomy. Urol Sci [serial online] 2020 [cited 2021 Jan 17];31:273-6. Available from: https://www.e-urol-sci.com/text.asp?2020/31/6/273/305101




  Introduction Top


Percutaneous nephrolithotomy (PCNL) was considered a safe and efficient method for removing kidney stones with a relatively low incidence of complications.[1] The success of PCNL was assessed in the absence of residual stone fragments under conventional X-rays or computed tomography (CT) or when clinically insignificant residual fragments (CIRFs) were not observed and the rate of complication was low.[1] The complication rate of PCNL can vary according to the complexity of the stone.

Thomas et al. divided stones into simple (isolated renal pelvis or isolated caliceal stones) or complex (partial or staghorn, renal pelvis stones accompanying caliceal stones, regardless of size). They did not find a consistent correlation between the severity of the complications with complexity, but they found a nonstatistically significant greater success rate for simple stones compared with complex ones.[2] Turna et al. used a combination of stone surface area and stone type (i.e., pelvic, caliceal, multiple, partial, or complete staghorn) and found that the stone type had the most significant effect on blood loss.[3] The stone size has been defined as the largest diameter on plain abdominal radiography by Olbert et al., who found it to be significantly related to the duration of surgery and the length of inpatient stay but not related to the complication rate or stone-free status.[4]

Guy's stone score (GSS) was validated and found reliable to predict the outcome.[5] GSS used abdominal X-ray examination and intravenous urography to predict the success rate after PCNL. GSS categorized PCNL into four grades of complexity (Grades I to IV) according to the medical history and noncontrast CT scan variable.[2]

Despite advances in surgical technology and techniques, it is very important for surgeons and patients to do surgical planning and preoperative consultation. There are several scoring systems before PCNL action, with one of the system schemes being GSS.[1],[6],[7] GSS was first published and proved to be easy to apply, also correlating well with success rates and complications.[8] This study aims to determine the success rate of PCNL based on GSS and its complications.


  Methods Top


This is a prospective cohort study. The subjects of this study were patients with kidney stones who underwent PCNL at Gunung Jati Regional Hospital from October 2018 to November 2019. Data were taken in the form of age, gender, operating time, hemoglobin loss, hospital stay, residual stone, and measurement of GSS. All of the procedures were standard supine PCNL and performed by one urologist. The operating time and blood transfusion were recorded. A follow-up was performed to see the complications assessed using the modified Clavien score, and the stone-free status was assessed by abdominal radiography. Stone-free status was considered positive if the patient was either stone-free or had any CIRFs, defined as <4 mm, nonobstructive, noninfectious, and asymptomatic residual fragment. All of the data were served in the form of tables using Spreadsheet Microsoft Excel.

For analysis purposes, all GSS Grades I and II were considered as a simple stone and GSS Grades III and IV were considered as a complex stone. Both groups were compared for stone-free rate (SFR) status and complications. For numerical data, statistically significant testing was done using an independent t-test, and for categorical data, Mann–Whitney U test was used with P < 0.05 being considered significant. All the analysis was performed using SPSS Inc. Released 2009. PASW Statistics for Windows, Version 18.0. Chicago: SPSS Inc.18. Ethics permission was obtained from the Health Research Ethics Committee and the Director of Human Resources and Education at Hasan Sadikin Academic Medical Center, Indonesia. Written informed consent was obtained from the patient(s) for their anonymized information to be published in this article.


  Results Top


A total of 198 patients were included in this study. GSS classification found that 37.4% of patients were in Grade I, 32.8% were in Grade II, 14.1% of patients were in Grade III, and the rest were in GSS Grade IV. It was found that the mean age of the population was 52.2 years old. Male gender was dominant with 55.56% of cases, and the percentage of the right kidney was higher than the left kidney with 55.56% of cases. The demographic data are listed in [Table 1].
Table 1: Demographic data based on Guy's Stone Score

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Hemoglobin loss was found the highest in GSS 4 (1.7 ± 1.1 mg/dL). The average duration of PCNL was 53.8 min. GSS Grade IV had the longest average gross operating time of 89.8 ± 29.1 min, with a total operating time of 75.8 ± 30.2 min. Stone fragment removal time was 32.5 min in GSS Grade IV, which also had the longest duration of 67.4 ± 30.2 min, followed by Grade III with 40.26 ± 33.0 min. X-ray time was longer in Grade IV with 220.8 ± 130.6 s, followed by Grade II with 157.8 ± 108.2 s. The length of hospital stay was 2.3 days. There was no difference in the length of stay between all grades.

About 27 patients (13.6%) still had residual stones and 170 (86.4%) did not. Patients with GSS IV had the most residual stones (15 out of 31 patients), followed by GSS III with nine patients. GSS I and II left only one and two patients, respectively, with residual stone [Figure 1]. Almost all GSS Grade I–IV patients treated by PCNL were classified as Clavien I [Figure 2] and [Table 2].
Figure 1: Percutaneous nephrolithotomy successful rate according to guy's stone score based on rest stone

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Figure 2: Percutaneous nephrolithotomy successful rate according to guy's stone score evaluate by clavien grading score

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Table 2: Percutaneous nephrolithotomy outcome based on Guy's Stone Score

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Our analysis based on stone complexity is shown in [Table 2]. There were only 3 (1.8%) residual stone cases in the simple stone group. On the other hand, our study found 24 (41.6%) residual stone cases in complex stone cases. Statistical analysis showed a significant difference between the two groups for stone-free status (P = 0.000). Both total operating time and stone fragmentation time were significantly higher in the complex stone group (P = 0.000 each). The total operating time in the simple stone group was 31.58 ± 20.513, with the mean total time in the complex stone group nearly double which was 62.46 ± 33.767 min. The mean fragmentation time in the simple stone group was 23.25 ± 20.002 min, with the complex stone group being 54.78 ± 34.079 min. The mean X-ray time was 155.17 ± 110.036 s or about 2–3 min in the simple group and 188.92 ± 123.806 s or about 3 min in the complex group, which was not statistically significant (P = 0.061). There was no significant difference in Hb loss between simple (GSS I and II) and complex stone (GSS III and IV) groups (P = 0.176) which was 1.09 ± 1.485 mg/dL and 1.43 ± 1.045 mg/dL, respectively. For complication, based on the Clavien grading score (CGS), there was no significant difference between simple and complex stone groups (P = 0.277) where almost all operations in both the simple and complex groups were included in CGS I (94.2% and 96.6%, respectively)


  Discussion Top


Kidney stones can affect all ages, genders, and races. In this study, it was seen that men were more dominant compared to women, with the male percentage reaching 55.56%. These results were similar to the epidemiological studies that also showed that kidney stones are more common in men between the ages of 20 and 49 years old.[9] However, this study found that the average age of the patients with kidney stones treated by PCNL was 52.5 years old, with a range of 1–90 years. This difference in the mean age can be due to differences in the selection of the management of kidney stones.

Although minimally invasive, PCNL is still considered a major operation with its own risk of complications and there is no guarantee that it will be completely stone-free. Therefore, Thomas and colleagues have reported a scoring system to assess the complexity of PCNL, namely, GSS, to predict the possibility of stone-free results preoperatively. GSS categorized PCNL cases into four grades of complexity (Grades I–IV) depending on the patient's past medical history and noncontrast computed tomographic-based variables such as larger numbers of stones, staghorn stones, stones located in upper calyces, and abnormal patient's anatomy that will increase the overall complexity of PCNL. GSS combined these variables and the grades of complexity from Grade I to Grade V, where level I is the least complex grade and Grade IV is the most complex grade.[2]

This study showed that the higher the GSS grade of the patient, the longer the gross surgery time and the total duration of surgery time. This can be seen in patients with GSS Grade I that had an average gross operating time of 45.9 min and the total operating time of 29.93, while the average gross operating time in patients with GSS Grade IV was 89.8 and total operating time was 75.8 min with total operating time for the complex stone group (GSS III and IV) being significantly longer than the simple one (GSS I and II) with almost twice. Research by Jiang et al. in their meta-analysis showed that the average length of PCNL surgery was 167 min and the analysis test found a significant relationship between GSS grading and PCNL operating time.[10] Research by Khalil et al. also showed that in patients with GSS I, GSS II, GSS III, and GSS IV, the operating time was 69.5 min, 111.4 min, 128.2 min, and 153.9 min, respectively. Khalil et al. also showed that there were statistically significant differences between the time of surgery and the amount of blood transfusion needed on the GSS score.[11] A study by Lojanapiwat showed that there was no significant difference in blood transfusion needed in each GSS where it is most likely that the blood loss was only associated with the stone composition. This result was similar to our study in that the Hb loss was found not to be significantly different.

According to the study of Mandal et al., complications appear more often in patients with higher GSS scores. Based on the study, they found a SFR of 100% in the GSS I, 74% in the GSS II, 56% in the GSS III, and 0% in the GSS IV.[5] Furthermore, the SFR in the study of Thomas et al. was 81% in the GSS I, 72.4% in the GSS II, 35% in the GSS III, and 29% in the GSS IV.[2] This study also found that after the PCNL procedure, 27 patients still had leftover stones while 171 patients did not have leftover stones. Patients with GSS IV had the most residual stone (15 out of 31 patients) followed by GSS III with nine patients with stones out of 19 patients. Our analysis also found that in the stone-free status, there was a significant difference between simple stone (GSS I and II) and complex stone groups (GSS III and IV). These results must be investigated further to see the factors that influence the results of stone cleanings in GSS I, II, III, and IV so that intervention can be done to reduce the number of the remaining stones in the PCNL procedure.

Research by Mandal et al. who conducted a study of 278 patients and performed PCNL on 116 kidney units showed that the most frequent complications were in GSS III and IV.[5] Significant complications occurred in higher GSS grade. However, in this study, it was found that almost all patients treated by PCNL were categorized as Grade I in the CGS. There were 2 death cases in the simple stone population, because of heart comorbidity owned by patients that led to sudden cardiac arrest in the recovery room. There was also no significant difference between the simple and complex groups in complications statistically, which indicated that there were good techniques and patient handling during operation.


  Conclusion Top


The success rate of PCNL based on guy's scoring system at Gunung Jati Regional Hospital is quite good. There was a significant difference in the SFR between groups due to the bigger stone as it increased in grade, but in this study, we found that the percentage of patients with remaining stones was <50% in each group. The operating procedure time was longer in the complex stone group compared with the simple stone group. However, there was no difference between the simple and complex stone groups in PCNL complications. Almost all patients with GSS I experienced post-PCNL complications when assessed with CGS, which indicated a good surgical practice.

Financial support and sponsorship

This research received Universitas Padjadjaran internal research grant.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Rathee V, Vivec HC, Khan SW, Singh A, Shukla PK, Verma A, et al. Comparison of guy's vs STONE nephrolithometry scoring systems in predicting the success rate of PCNL. J Clin Urol 2017;10:423-9.  Back to cited text no. 1
    
2.
Thomas K, Smith NC, Hegarty N, Glass JM. The Guy's stone score-grading the complexity of percutaneous nephrolithotomy procedures. Urology 2011;78:277-81.  Back to cited text no. 2
    
3.
Turna B, Umul M, Demiryoguran S, Altay B, Nazli O. How do increasing stone surface area and stone configuration affect overall outcome of percutaneous nephrolithotomy? J Endourol 2007;21:34-43.  Back to cited text no. 3
    
4.
Olbert PJ, Hegele A, Schrader AJ, Scherag A, Hofmann R. Pre- and perioperative predictors of short-term clinical outcomes in patients undergoing percutaneous nephrolitholapaxy. Urol Res 2007;35:225-30.  Back to cited text no. 4
    
5.
Mandal S, Goel A, Kathpalia R, Sankhwar S, Singh V, Sinha RJ, et al. Prospective evaluation of complications using the modified clavien grading system, and of success rates of percutaneous nephrolithotomy using guy's stone score: A single-center experience. Indian J Urol 2012;28:392-8.  Back to cited text no. 5
[PUBMED]  [Full text]  
6.
Lojanapiwat B, Rod-Ong P, Kitirattrakarn P, Chongruksut W. Guy's stone score (GSS) based on intravenous pyelogram (IVP) findings predicting upper pole access percutaneous nephrolithotomy (PCNL) Outcomes. Adv Urol 2016 Jan 1;2016.  Back to cited text no. 6
    
7.
Sharma L, Lavania S, Khetarpal A, Ahmed N, Mathur R, Yadav R. Outcome of PCNL-success & complications. 2016;15:121-5.  Back to cited text no. 7
    
8.
Matlaga BR, Hyams ES. Stones: can the Guy's stone score predict PNL outcomes? Nat Rev Urol 2011;8:363-4.  Back to cited text no. 8
    
9.
Alelign T, Petros B. Kidney stone disease: An update on current concepts. Adv Urol 2018 Feb 4;2018.  Back to cited text no. 9
    
10.
Jiang K, Sun F, Zhu J, Luo G, Zhang P, Ban Y, et al. Evaluation of three stone-scoring systems for predicting SFR and complications after percutaneous nephrolithotomy: A systematic review and meta-analysis. BMC Urol 2019;19:57.  Back to cited text no. 10
    
11.
Khalil M, Sherif H, Mohey A, Omar R. Utility of the guy's stone score in predicting different aspects of percutaneous nephrolithotomy. Afr J Urol 2018;24:191-6.  Back to cited text no. 11
    


    Figures

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    Tables

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