Value of preoperative stone scoring systems in predicting the results of percutaneous nephrolithotomy.

353 Central European Journal of Urology UROLITHIASIS ORIGINAL PAPER Value of preoperative stone scoring systems in predicting the results of percutaneous nephrolithotomy Şükrü Kumsar, Hüseyin Aydemir, Fikret Halis, Osman Köse, Ahmet Gökçe, Oztug Adsan Sakarya University Training and Research Hospital, Sakarya, Turkey Citation: Kumsar S, Aydemir H, Halis F, Köse O, Gökçe A, Adsan O. Value of preoperative stone scoring systems in predicting the results of percutaneous nephrolithotomy. Cent European J Urol. 2015; 68: 353-357. Article history Submitted: Jan. 25, 2015 Accepted: June 24, 2015 Published on-line: Oct. 15, 2015 Corresponding author Şükrü Kumsar Sakarya University Training and Research Hospital 54100 Sakarya, Turkey phone: +90 264 255 2106 Introduction Guy’s Stone Score and S.T.O.N.E. Nephrolithometry nomograms have been introduced for systematic and quantitative assessment of kidney stones. The aim of this study was to reveal the value of two scorings systems, Guy and S.T.O.N.E, most frequently used for predicting postoperative stone-free status prior to Percutaneous Nephrolithotomy (PCNL), in the prediction of postoperative results of PCNL. Material and methods We retrospectively examined patients who underwent PCNL. Preoperative abdominopelvic computerized tomography images of these patients were reviewed and scored according to the Guy and S.T.O.N.E. systems. The relationship between the Guy and S.T.O.N.E. scores, and their postoperative stone-free status, complications based on Clavien system, operation time, fluoroscopy time and period of hospitalization was compared. Results We identified a total of 102 patients who underwent PCNL between 2010 and 2014, having met the inclusion criteria. The relationships between the total S.T.O.N.E score and Clavien score (p <0.001); time of operation (p = 0.012) and stone-free status (p <0.001); Guy stone score and Clavien score (p <0.001); and period of hospitalization (p <0.001) and time of operation (p <0.001) were found to be statistically significant. There was no statistically significant relationship between Guy score and stone-free status and no statistically significant relationship was found between fluoroscopy time and both stone scoring systems. Conclusions Guy and S.T.O.N.E. scoring systems may be used as effective instruments particularly for predicting postoperative complications. Key Words: complication ‹› computerized tomography ‹› percutaneous nephrolithotomy ‹› renal stone INTRODUCTION Percutaneous nephrolithotomy (PCNL) is a minimally-invasive treatment modality, considered by guidelines as primary care regarding treatment of >20 mm kidney stones, and as such, is now applied in a number of centers [1, 2]. However, there has been a remarkable increase in complication rates despite developments in surgical techniques and technology [3, 4]. The most frequent complications of PCNL include extravasation (7.2%), bleeding requiring a blood transfusion (11.2–17.5%) and fever (21–32.1%) [5]. Cent European J Urol 2015; 68: 353-357 Septicemia (0.3–4.7%), colon injury (0.2–4.8%), and pleural injury (0–3.1%) are rare complications [5]. Nephrectomy (0.4–1.1%) and patient’s death (0.05%) are more serious and rarer complications after PCNL [6]. The complication rates increase due to the presence of accompanying diseases such as renal failure, diabetes mellitus, and obesity [5]. Computed tomography (CT) as the most frequently used imaging method in identifying pre-PCNL stones, plays a very important role in preoperative evaluations in terms of characterization of stones, renal caliceal anatomy and the identification doi: 10.5173/ceju.2015.552 354 Central European Journal of Urology of anatomic proximity. In addition, it is possible to carry out systematic and quantitative evaluations with the help of Guy and S.T.O.N.E. stone scoring systems that are acquired based on preoperative CT findings [7, 8]. The Guy stone scoring system involves four grades (Grades 1, 2, 3, and 4) according to the caliceal localization of stones, the presence of single or multiple stones and renal anatomic structure [7]. The S.T.O.N.E. scoring system, on the other hand, is an acronym of the English initials the five parameters: stone size, tract length, obstruction, number of calyxes retained, and stone density [8]. These nomograms allow the surgeon to form an opinion regarding the possible postoperative and preoperative complications, as well as the surgical success, and enable them to share these opinions with their patients [7, 8, 9]. Another potential advantage of using these nomograms is that they enable us to standardize operation results and compare them with other series. Until now, there has been a paucity of studies comparing such standardized nomograms with different series and also comparing the different nomograms with one another. The purpose of this study was to reveal the value of two different scoring systems in predicting the postoperative results of PCNL. MATERIAL AND METHODS We retrospectively examined patients who underwent PCNL, between November 2010 and August 2014 at our hospital. Exclusion criteria included patients younger than 18 years old, a history of prior surgery on the ipsilateral kidney, nephrostomy tube or stent placement in the ipsilateral kidney prior to surgery, and patients with no CT images available preoperatively. Preoperative abdominopelvic computerized tomography images of the patients were reviewed and scored according to the Guy and S.T.O.N.E. scoring systems. S.T.O.N.E. scores were categorised as low complex, moderate complex and high complex. Guy’s score 1 (GS 1): a solitary stone in the mid and/or lower pole or in the renal pelvis with normal anatomy. Guy’s score 2 (GS 2): a solitary stone in the upper pole; multiple stones in a patient with simple anatomy; or a solitary stone in a patient with abnormal anatomy. Guy’s score 3 (GS 3): multiple stones in a patient with abnormal anatomy or in a calyceal diverticulum or partial staghorn calculus (defined as a stone evolving the renal pelvis and at least 2 calices). Guy’s score 4 (GS 4): a complete staghorn calculus (all calices and the pelvis occupied by stones) or any stone in a patient with spina bifida or a spinal injury. The S.T.O.N.E. score can vary from a minimum of 5 to a maximum of 13. A score of 5–6 denotes a low complex stone, 7–8 is regarded moderate complex and a score of 9–13 indicates a high complex stone [7, 8]. The demographic characteristics, presence of residual stones, operation time, period of hospitalization, fluoroscopy time and complications were recorded from patient files. PCNL Technique As described in the literature [9], briefly, access was obtained under C-arm fluoroscopy using an 18 gauge needle with the patient in the prone position. The tract was dilated with amplatz dilatators. Fragmentation of the stone burden was accomplished using a pneumatic (Vibrolith®, Elmed, Ankara, Turkey) or ultrasonic (Sw (...truncated)