Urolithiasis is a frequent and increasingly prevalent affliction globally, affecting approximately 5% of women and 12% of men in the general population [1]. Consequently, the sequelae and downstream complications of kidney stone disease are observed with rising frequency. Most patients presenting with calculi-related renal insufficiency experience stabilization or substantial recovery of kidney function following prompt intervention aimed at complete stone removal[2,3] .The two most formidable complications of untreated or neglected urolithiasis are obstructive renal failure and sepsis [4]. With timely intervention and meticulous management, however, both complications can be successfully addressed, frequently leading to remarkable recovery of renal function. While the fundamental pathophysiological mechanisms causing renal insufficiency in obstructive uropathy are well established, stone disease introduces additional complex variables. In calculous obstruction, functional impairment is dictated not merely by the mechanical blockage of urine flow, but also by compounding elements such as the stone composition, duration of obstruction, presence and virulence of infection, stone anatomical location, and underlying renal parenchymal integrity [5,6]. The compounding interplay of urinary stasis, infection, recurrent instrumentation, and pre-existing medical comorbidities frequently leads to varying degrees of acute-on-chronic kidney injury [7]. Clinical delays in recognizing obstruction or referring patients to specialized urological care often result in irreversible parenchymal damage and advanced renal failure among patients managed conservatively [3]. Given these clinical challenges, evaluating preoperative, intraoperative, and postoperative prognostic determinants is crucial for optimizing therapeutic strategies and predicting functional recovery [2]. This prospective study evaluates 30 patients presenting with urolithiasis and elevated renal parameters, systematically examining the clinical factors influencing treatment outcomes, procedural modalities, and postoperative renal functional recovery. Aims and Objectives • To analyze the clinical and preoperative factors contributing to renal insufficiency in patients presenting with urinary stone disease. • To evaluate the various minimally invasive and open surgical interventions utilized in the management of complex urolithiasis. • To assess the key prognostic determinants influencing the functional outcome and recovery of renal parameters following procedural intervention. • To evaluate the extent of postoperative renal function improvement and stabilization on medium-term follow-up.

This prospective observational study was conducted in the Department of Urology at Chettinad Hospital and Research Institute, Chennai, over a 1.5-year period from January 2024 to June 2025. A total of 30 patients meeting the inclusion criteria were enrolled following Institutional Human Ethics Committee clearance and written informed consent. Inclusion Criteria: Patients diagnosed with urolithiasis presenting with elevated renal function parameters (serum creatinine ≥ 1.5 mg/dL). Exclusion Criteria: Patients with a known prior diagnosis of chronic kidney disease (CKD) or individuals with congenital urinary tract anomalies resulting in anatomical obstruction. Preoperative evaluation included detailed clinical history, physical examination, baseline laboratory investigations (complete blood count, renal function tests, serum electrolytes, random blood sugar, HbA1c, and urine culture/sensitivity), and imaging studies (plain X-ray KUB, ultrasonography, and non-contrast CT KUB where indicated). Patients presenting with severe infection or urosepsis underwent emergency urinary decompression via percutaneous nephrostomy (PCN) or retrograde double-J stenting prior to definitive stone management. Definitive stone removal was achieved via ureteroscopic lithotripsy (URSL), percutaneous nephrolithotomy (PCNL), retrograde intrarenal surgery (RIRS), or open surgery depending on stone burden and location [4,8]. Postoperative surveillance closely monitored serum creatinine trends, resolution of proteinuria, residual stone fragments, and urinary tract infection recurrence.

Demographic and Clinical Profile: Among the 30 patients evaluated, 21 (70%) were male and 9 (30%) were female, demonstrating a male predominance. The patient age ranged from 18 to 60 years, with a mean age of 44 years. The peak incidence was observed in the 41–50 years age group (43%). Symptom duration prior to presentation ranged from less than one month to four months, with the majority of patients (17 patients) presenting within the first month. Comorbidities and Infections: Comorbid illnesses were documented in 14 patients (46.6%), with diabetes mellitus being the most common (10 patients, including 4 with coexisting hypertension), followed by tuberculosis (3 patients), asthma (2 patients), and ischemic heart disease (1 patient). Positive preoperative urine cultures were observed in 13 patients (43%), predominantly yielding Escherichia coli (6 patients) and Proteus species (5 patients), alongside mixed growth (2 patients). Table 1: Patient Demographic Data, Comorbidities, and Preoperative Clinical Parameters (N=30) Parameter / Category Sub-category / Variables Number of Patients (n) Percentage (%) Gender Male 21 70.0% Female 9 30.0% Age Distribution 20–30 years 3 10.0% 31–40 years 8 26.7% 41–50 years 13 43.3% 51–60 years 6 20.0% Symptom Duration 0–1 month 17 56.7% 1–2 months 8 26.7% 2–3 months 4 13.3% 3–4 months 1 3.3% Comorbidities Diabetes Mellitus 10 33.3% Hypertension 4 13.3% Tuberculosis 3 10.0% Asthma 2 6.7% Ischemic Heart Disease 1 3.3% Urine Pathogens Escherichia coli 6 20.0% Proteus species 5 20.0% Mixed Bacterial Growth 2 6.7% No Growth / Sterile 17 56.7% Preoperative Creatinine 1.5 – 2.5 mg/dL 23 76.7% 2.6 – 3.5 mg/dL 5 16.7% 3.6 – 4.5 mg/dL 1 3.3% 4.6 – 5.5 mg/dL 1 3.3% Stone Characteristics and Interventions: Stone sizes ranged from 1 cm to 5 cm. Anatomical distribution revealed pelvic stones in 5 patients, staghorn calculi (complete and partial) in 5 patients, and ureteric calculi in 20 patients (including bilateral presentations). Minimally invasive procedures formed the mainstay of treatment: ureteroscopic lithotripsy (URSL) was performed in 18 patients (60%), percutaneous nephrolithotomy (PCNL) in 7 patients (23.3%), open surgery in 3 patients (10%), and retrograde intrarenal surgery (RIRS) in 2 patients (6.7%). Renal Functional Outcomes: Preoperative serum creatinine levels ranged from 1.5 mg/dL to 5.5 mg/dL. Complete stone clearance was achieved in 27 patients (90%), while 3 patients retained clinically insignificant residual fragments managed via ESWL or observation. At the two-week and subsequent follow-up evaluations, normal serum creatinine levels (< 1.2 mg/dL) were restored in 21 patients (70%), while 9 patients exhibited mild-to-moderate residual elevation with a steady, decreasing trend. Overall, 83.33% of patients demonstrated marked renal functional improvement, and 16.67% achieved functional stabilization. Table 2: Surgical Procedures Performed and Postoperative Outcomes (N=30) Clinical Parameter Category / Outcome Measure Number of Patients (n) Percentage (%) Surgical Intervention Ureteroscopic Lithotripsy (URSL) 18 60.0% Percutaneous Nephrolithotomy (PCNL) 7 23.3% Open Surgery (Pyelo/Ureterolithotomy) 3 10.0% Retrograde Intrarenal Surgery (RIRS) 2 6.7% Stone Clearance Complete Clearance (Clear) 27 90.0% Residual Fragments (Managed/Observed) 3 10.0% Postoperative Creatinine < 1.2 mg/dL (Normal) 21 70.0% 1.2 – 1.5 mg/dL (Mild Elevation) 5 16.7% 1.6 – 2.0 mg/dL (Moderate Elevation) 4 13.3% Postoperative UTIs Escherichia coli 4 13.3% Proteus species 2 6.7% No Infection 24 80.0% Functional Trajectory Renal Function Improvement 25 83.3% Renal Function Stabilization 5 16.7%

Urolithiasis associated with renal insufficiency remains a critical urological emergency requiring prompt diagnosis and systematic management [2]. Our prospective findings align closely with established literature emphasizing that obstruction, infection, and stone burden are pivotal determinants of renal parenchymal injury [5]. The predominance of male patients and middle-aged adults in our cohort mirrors broader epidemiological trends in urolithiasis across Asia and worldwide [1]. Our study highlights that early decompression and aggressive stone clearance yield exceptional renal functional recovery. Over 83% of patients showed significant improvement in serum creatinine following intervention, reinforcing the reversible nature of obstruction-induced acute-on-chronic renal impairment when addressed expeditiously [3]. Furthermore, baseline serum creatinine emerged as the most reliable predictor of renal recovery potential. Patients presenting with extreme azotemia or advanced parenchymal thinning (cortical atrophy) experienced more modest functional improvement, underscoring the necessity of early urological referral before irreversible nephron loss occurs [9]. Infectious calculi, particularly those associated with Proteus-driven struvite stones and diabetic nephropathy, present unique management hurdles [6]. Postoperative fever and recurrent urinary tract infections were effectively controlled with targeted antibiotic therapy and glycemic control. Moreover, stone location and bilateral obstruction significantly influenced clinical presentation and baseline impairment, yet timely relief of obstruction in solitary kidneys or bilateral ureteric calculi resulted in substantial functional salvage, corroborating findings by prior investigators [7,10]. Additionally, modern endourological advancements have enabled safer, highly efficient stone clearance with minimal parenchymal trauma [8].

Calculus-related renal insufficiency is largely reversible with prompt diagnostic evaluation, effective infection control, and early surgical intervention aimed at complete stone clearance [2]. Baseline serum creatinine, cortical thickness, and associated comorbidities such as diabetes mellitus are vital predictors of long-term functional recovery [3]. Implementing structured multidisciplinary follow-up protocols, metabolic evaluations, and renal protective measures significantly reduces morbidity and preserves long-term renal function in this vulnerable patient population.

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