Upper Urinary Tract Stones Clinical Trial
Official title:
Role of Nephrolithometric Scoring Systems in Prediction of Percutaneous Nephrolithotomy Outcomes in Adult
Prospective study is to compare between different nephrolithometric scoring systems in prediction of PCNL outcomes in terms of efficacy , success rate and safety in Adult patients with UUT stones unilateral or bilateral, single or multiple, Pelvic or calyceal, primary or recurrent, both gender attending Assuit Urology & Nephrology University Hospital.
The incidence of urolithiasis is approximately 5% to 10% in the general population, In an
active urologic department, 30% of the surgical working load is known to be related to
treatment of renal and ureteral stones (1, 2). Since the original description of stone
removal through a percutaneous nephrostomy tract by Fernstrom and Johansson in 1976,
percutaneous stone removal has evolved into a highly developed procedure practiced by many
urologists (3). Several new techniques and technologies recently have emerged that simplified
the procedure, allowed to take on more challenging cases and made it safer and less painful
for patients (4).
Nephrolithometric scoring systems have been introduced to overcome limitations for systematic
and quantitative assessment of the outcomes of PCNL. Moreover, preoperative patient
counselling necessitates the development of an integrated scoring system to assess PCNL
complexity for optimal decision-making Nephrolithometric scoring systems include the Guy's
Stone Score (5), S.T.O.N. E. (Stone Size, Tract length, Obstruction/hydronephrosis, Number of
involved calyces, Essence/Hounsfield units) nephrolithometry scoring system (6), The Clinical
Research Office of the Endourology Society (CROES) nomogram (7), and the Seoul National
University Renal Stone Complexity (S-ReSC) score (8,9). All these nephrolithometry scoring
systems (NLSS) aim for preoperative prediction of stone-free status (SFS) and complications
through assessment of the complexity of different cases undergoing PCNL. NLSS do not only
consider the imaging criteria of stones and renal anatomy, but also relevant patient
characteristics such as body mass index, previous renal surgery, and surgeon experience. The
Guy's Stone Score, S.T.O.N.E. nephrolithometry score and CROES nomogram consist of 11
variables, including four shared parameters (stone size, location, number, and staghorn
status). Other variables which are considered by these three NLSS are stone density, renal
anatomy, tract length, obstruction of renal pelvis, case load/year, prior treatment history,
and the presence of spina bifida or spinal injury.
The Guy's Stone score categorises PCNL cases into four grades, increasing in complexity from
Grade 1 to Grade 4, depending on patients' past medical history and non-contrast CT (NCCT)
(5).
The S.T.O.N.E. nephrolithometry scoring system assesses PCNL complexity by nine different
possible scores, ranging from 5 to 13, according to five NCCT-calculated parameters including
stone size, tract length, obstruction/ hydronephrosis, number of involved calyces, Essence/
Hounsfield units (6).
the CROES nephrolithometric nomogram predicts treatment success using plain X-ray of the
kidneys, ureters and bladder considering the stone burden, count, and location, in addition
to case volume and prior stone treatment (7).
The total score to predict the chance of treatment success is the sum of individual scores
derived from each predicting variable; the higher the score, the higher the chance of
treatment success, while a patient with a low score has a low chance of achieving a SFS (7).
On the other hand, the S-ReSC score is calculated by counting the number of sites involved in
the renal pelvis and calyces, regardless of stone parameters or renal anatomy. This system
assigns a score from 1 to 9 depending mainly on the number of sites involved; the renal
pelvis (1), superior and inferior major calyces (2-3), anterior and posterior minor calyces
of the superior (4-5), middle (6-7), and inferior calyces (8-9).
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