J Aziz Fatm Med Den College JANUARY – JUNE 2022; VOL. 4, NO. 1 37 Original Article Guy’s Stone Scoring in Predicting Postoperative Residual Stone Muhammad Waqas Iqbal, Farhan Jamshed, Adeen Akram, Nauman Khalid, Muhammad Saifullah, Muhammad Akram Malik ABSTRACT Objective: To determine the frequency of postoperative residual stone based on preprocedural Guy’s scoring system. Methodology: This cross-sectional descriptive study was conducted from1st June 2018 to 30th November 2019 at University Medical College Faisalabad. All patients with stones in the kidney undergoing PCNL, 20 to 60 years of age of both genders were included. Patients with secondary stones due to pelviureteric junction obstruction, CRF and recurrent stones were excluded. In all patients Guy’s scoring was measured. Then all patients underwent PCNL. After 24 hours of operation, CT scan was done in each patient and residual stone (present/abse nt) was noted. Results: This study was comprised of 91 patients of age ranged from 20- 60 years. Fifty-three patients (58.24%) were males and 38 (41.76%) females. Seven (7.69%) were of Guy’s grade I, 48(52.75%) grade II, 21(23.08%) grade III and 15 of grade IV. Number of patients with residual stone was 09 (9.89%), 0.0% of GS 1, 12.5% of GS 2, 4.76% of GS 3 and 13.33% of GS 4 patients had residual stone. Conclusion: Pre-PCNL Guy’s scoring is easy, rapid and useful for predicting the residual stone after percutaneous nephrolithotomy. KEYWORDS: Residual stone, Guy’s scoring system, Extracorporeal shockwave lithotripsy INTRODUCTION Nephrolithiasis is a common disorder with estimated prevalence of 1-13% in various regions of the world.1 Precipitating factors of kidney stone disease include age, gender, diet, lifestyle, socioeconomic status, geographical location and race/ethnicity resulting in various incidence rates in different countries.2,3 Urinary stone disease has affected mankind since antiquity. It has been even found in Egyptian Mummies.4 Nephrolithiasis is a recurrent disorder. In some studies recurrence rate has been ____________________________________________________________ Dr. Muhammad Waqas Iqbal MBBS, FCPS Assistant Professor University Medical College, FSD Dr. Farhan Jamshed MBBS, FCPS Senior Registrar University Medical College, FSD Dr. Adeen Akram MBBS Postgraduate Resident (PGR) District Headquarter (DHQ) Hospital, FSD Dr. Nauman Khalid MBBS, FCPS Assistant Professor University Medical & Dental College, FSD Dr. Muhammad Saifullah MBBS, FCPS Senior Registrar District Headquarter (DHQ) Hospital, FSD Dr Muhammad Akram Malik MBBS, FCPS Professor University Medical College, FSD Correspondence: Dr. Muhammad Akram Malik Email: akrammlk@yahoo.com reported from 21% to 53%. Most of the stones are of calcium oxalate (75%-90%). Other components were uric acid (5%−20%), calcium phosphate (6%−13%) and struvite (2%−15%).5,6 New techniques have been developed for the management of renal stones with the advances in technology in this modern era. Extracorporeal shockwave lithotripsy (ESWL), Percutaneous nephro- lithotomy (PCNL), Retrograde intrarenal surgery (RIRS), and Laparoscopic stone surgeries have replaced open surgical procedures in majority of cases.7 Percutaneous Nephrolithotomy (PCNL) is now consi- dered as first line standard treatment for large renal stones >2cm. As the incidence of renal stone is increasing, procedure of PCNL has become increa- singly popular. Stone free rate after PCNL and its complications are topic of discussion due to increasing number of procedures in the world. The objective and goal of PCNL is the provision of maxi- mum stone clearance with minimal rate of compli- cations.7 Different preoperative factors which affect the outcome of PCNL are size & site of the stone, patient’s characteristics and renal anatomy.8 To date computed tomography (CT) is considered as the most important imaging investigation in renal stones prior to PCNL. CT plays a very important role in preoperative assessment of stone’s characteristics and renal anatomy. Various scoring systems like Guy’s scoring, CROES nomogram and S.T.O.N.E., are based on findings of preoperative CT.9,10 Aims of the study was to determine the frequency of J Aziz Fatm Med Den College JANUARY – JUNE 2022; VOL. 4, NO.1 38 postoperative residual stone based on pre-procedural Guy’s scoring system. METHODOLOGY It was a descriptive study conducted at University Medical College Faisalabad from June, 01, 2018 to November, 30, 2019. All patients with kidney stones of either gender, with age range 20-60 years were included into this study. Diagnosis was confirmed by plain computerized tomography (CT). Ethical approval was taken from ethical approval committee (TUF/Dean/2018 dated May, 15, 2018). Preoperatively Guy’s scoring was done for each patient as follows: Guy’s stone score 1 (GSS1): a solitary stone in the mid/and or lower pole or in the renal pelvis with a normal anatomy and simple collecting system Guy’s stone score 2 (GSS2): a solitary stone in the upper pole; multiple stones in patients with simple anatomy; or a solitary stone in a patient with abnormal anatomy Guy’s stone score 3 (GSS3): multiple stones in a patient with abnormal anatomy or in a calyceal diverticulum or partial staghorn calculus Guy’s stone score 4 (GSS4): a complete staghorn calculus or any stone in a patient with spinal bifida or a spinal injury, calculus in patients with clinical neurological alternations (spinal cord injury, myelomeningocele) All patients underwent PCNL by experienced consultant. CT-scan was performed on 1st postoperative day to see any residual stone >2mm. Patients with secondary stones due to pelviureteric junction obstruction as assessed on Computed Tomography Urography (CTU), of chronic renal failure (s/creatinine >1.5 mg/dl) and with recurrent stones were excluded from study. Morbidly obese patients (BMI >37 kg/m2) and the Patients in which procedure was converted to open pyelolithotomy were also excluded. Statistical analysis: Social Science (SPSS) Version 20.0 was used to analyze the entered data. Quantitative data were presented as mean ± SD. Qualitative data were presented as frequency and percentage. Pre- operative Guy’s grading (1/2/3/4) and effect modifiers like age, gender & BMI were stratified. Post- stratification chi-square was used to assess their effect on postoperative residual stone and p-value ≤0.05 was taken as significant. RESULTS Total no of patients in this study was 91. Age ranged from 20- 60 years with mean age of 35.64 ± 8.12 years. Characteristics of Patients according to age, gender and BMI is shown in table 1. Male to female ratio was 1.4:1. Mean BMI was 27.73 ± 2.86 kg/m2. Table 1: Characteristics of Patients According to Age, Gender and BMI (N=91) Groups No. of Patients (N) Percentages (%) Age 20-40 69 75.82 41-60 22 24.18 Gender Male 53 58 Female 38 42 BMI (kg/m2) ≤27 44 48.35 >27 47 51.65 Fifty three patients (58.24%) were males and 38 (41.76%) females. Male to female ratio was 1.4:1. Mean BMI was 27.73 ± 2.86 kg/m2 (Table I). Mean preoperative Guy’s grading was 2.48 ± 0.86. Distribution of patients according to Preoperative Guy’s grading is shown in (Figure 1). Figure 1: Distribution of Patients According to Pre-Operative Guy’s Grading (n=91). GSS=Guy’s stone score Residual stone was present in 09 (9.89%) with none in grade 1 and 2(15.38%) in grade 4(table 2). 0 10 20 30 40 50 60 GSS1 GSS2 GSS3 GSS4 7(7.69%) 48(52.75%) 21(23.08%) 15(16.48%) p e rc e n ta g e s Muhammad Waqas Iqbal et al J Aziz Fatm Med Den College JANUARY – JUNE 2022; VOL. 4, NO.1 39 Table 2: Stratification of Residual Stone with Respect to Pre-Operative Guy’s Grading (n=91). Pre-operative Guy’s grading Residual stone P-Value Present N (%) Absent N (%) Grade 1 00 7 (100) 0.582 Grade 2 06 (12.5) 42 (87.5) Grade 3 01 (4.7) 20 (95.2) Grade 4 02 (13.3) 13 (86.6) p-value ≤0.05 taken as significant. Stratification of residual stone with respect to age, gender and BMI shows greater number of residual stones in age group of 41-60 years (Table 3). Table 3: Stratification of Postoperative Residual Stone with Respect to Age, Gender and BMI Groups (n=91). Groups Residual stone P-values Present N Absent N Age 20-40 04 65 0.021* 41-60 05 17 Gender Male 04 49 0.377 Female 05 33 BMI (kg/m2) ≤27 06 38 0.247 >27 03 44 p-value ≤0.05 taken as significant. DISCUSSION Percutaneous nephrolithotomy (PCNL) is being considered as procedure of choice for large and complex renal calculi and has replaced the open surgical procedures to greater extent.11Although PCNL is an endoscopic procedure with higher success rate and minimal complications, however stone free rate is not 100%.12Stone size, burden, and location, renal calyceal anatomy and associated hydronephrosis are different parameters which predict the outcome of PCNL. However, when these parameters are used individually, precise outcome of the procedure cannot be predicted.13 Due to this reason various scoring systems have been invented to predict the outcome of PCNL. These scoring systems are based on preoperative stone size/burden, renal calyceal anatomy and patient's characteristics (age/ gender/body built/BMI).14 Besides prediction of stone free rate, counseling of patient, refinement of procedure and adjustments of various training programs can be managed by these scoring.15 Various scoring systems have been developed to predict stone free rate and complications. Guy’s scoring system, the S.T.O.N.E. scoring system, the S-ReSC Scoring System of the Seoul National University and the CROES, are among the most commonly applied and evaluated. Guy’s scoring is easy to perform, simple and rapid to predict the outcome of PCNL.16-19 In our study, the percentage of patients with residual stone was 09 (9.89%). 0.0% of GS 1, 12.5% of GS 2, 4.76% of GS 3 patients and 13.33% of GS 4 had residual stone. In a study, 75% of the subjects were GS 1, 21% GS 2 and 3% GS 3. In this study, 66% of GS 3, 4% of GS 2 and 10% of GS had residual stone. 20Another published series reported residual stones in 70% of GS 1, 65% of GS 2 and 38% of GS 3 persons.21 Results of our study are comparable with these studies, however with better outcome in present study. Vicentini et al reported rates of 95% and 79 %, 59 % and 41% of stone-free patients in GS1, GS2 GS 3 and GS 4 scoring system respectively in their series involving 147 PCNL patients , and elaborated a significant association of Guy scores and stone-free rate.13 Kay Thomas evaluated residual stones in 100 patients who underwent PCNL, and found residual stones in 19% of grade I, 28% of grade II, 65% of grade III and 71% of grade IV.18 Results obtained by Kay Thomas and Vicentini et al are contradictory to the study conducted by Mandal et al19, who found stone free rate of 0%, 56%, 68%, 74%, for grade 1-4 respectively. As reported in all above mentioned series, Guy’s scoring system precisely discriminates between the two endpoints. Guy’s scoring system briefly creates two group of grades, good and bad. Grades 1 and 2 are considered as good and grades 3 and 4 are relatively bad group. Our study has age range from 20 - 60 years (mean = 35.64 ± 8.12 years). As the age and clearance of renal stone is concerned there is significant difference in terms of residual stone among two age groups. 29% of patients in age group 41-60 have residual stone as compared to 6% in age group 20-40 years(p-<0.021). In a study conducted by Rahul Gupta there is no difference in different age groups as far as stone free rate is considered (94% vs 92% respectively in older & young).22 Most probable causative factor for higher residual stone in the older age group in our study is obesity.23 No statistically significant difference in terms of residual stone with respect to gender (8% in Male and 13% in Female) and weight (14% in BMI ≤27 and 6% in BMI >27). These results are comparable to other series.23, 24 The Guy score has been validated externally in a large number of published series. In two separate series by Mandal and Ingimarsson, Guy’s scoring system effectively predicted SFR and has been externally validated.19,25 The Guy score has excellent interobserver reliability.25 Guy’s Scoring for Residual Stone J Aziz Fatm Med Den College JANUARY – JUNE 2022; VOL. 4, NO.1 40 CONCLUSION Pre-PCNL Guy’s is useful for predicting the residual stone after the procedure. 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Waqas Iqbal Study design, manuscript writing. Revised and approved the articles. Study design, acquisition of data and manuscript writing. Revised and approved the articles Dr. Farhan Jamshed Study design, acquisition of data and manuscript writing. Revised and approved the articles Dr. Adeen Akram Study design, acquisition of data, data analysis and interpretation and write up of results Dr. Nauman Khalid data analysis and interpretation and write up of results approve the final version of article. Dr. M. Saifullah Study design. Revising manuscript critically for important intellectual content and approve the manuscript Dr. M. Akram Malik Study design, critically Revising manuscript critically for important intellectual content and approve the manuscript All authors are equally accountable for research work and integrity Date of submission: 10-04-2021, Revised received: 16-12-2021, Accepted: 22-01-2022 Guy’s Scoring for residual stone