Urolithiasis remains one of the most common and challenging pathologies encountered in modern clinical urology, affecting approximately 5% of the global population with a lifetime prevalence ranging between 8% and 15% [1]. Characterized by high recurrence rates—approaching 50% over a five-year period—ureteric stone disease places a substantial clinical and economic burden on healthcare systems worldwide [1, 2]. Over the past few decades, the therapeutic paradigm for managing ureteral calculi has shifted dramatically from invasive open ureterolithotomy and laparoscopic approaches toward minimally invasive endo-urological interventions [3]. Ureteroscopy (URS) has emerged as the gold-standard first-line treatment for ureteric stones, offering high success rates exceeding 90% [3]. Central to the success of ureteroscopy is the choice of intracorporeal lithotripsy energy source used to fragment stones [4]. While various modalities such as electrohydraulic and ultrasonic lithotripters have seen declining use, pneumatic (ballistic) lithotripsy and Holmium:YAG (Ho:YAG) laser lithotripsy remain the two primary, highly dependable energy sources utilized globally [4, 5]. Pneumatic Lithotripsy: Introduced in the early 1990s with the Swiss LithoClast, pneumatic lithotripsy relies on compressed air to propel a metal projectile against a rigid probe, generating a ballistic "jackhammer" effect [5]. While favored for its cost-effectiveness, durability, and low maintenance requirements, its rigid design mandates straight working channels and is frequently associated with a higher rate of stone retropulsion [ 5, 6]. Holmium:YAG Laser Lithotripsy: Operating at a wavelength of 2100 nm, the Ho:YAG laser utilizes a pulsed thermal mechanism mediated by microscopic vaporization bubbles that generate localized shock waves [4]. Capable of fragmenting stones of all compositions and compatible with flexible fiber optics, holmium laser technology has revolutionized endourology, though it demands higher equipment costs and technical proficiency [4, 7]. Despite the widespread utilization of both modalities, ongoing debate persists regarding their comparative safety profiles, stone-free rates, stone retropulsion frequencies, and procedural efficiency—particularly in developing regions and variable stone locations [8]. This prospective observational randomized controlled study was designed to rigorously evaluate and compare the clinical outcomes and safety profiles of intracorporeal pneumatic lithotripsy versus Holmium:YAG laser lithotripsy in 100 patients undergoing ureteroscopic stone removal at the Chettinad Hospital and Research Institute [9]. By assessing parameters such as complete stone clearance, stone migration/retropulsion rates, intraoperative and postoperative complications, and the need for auxiliary procedures, this study aims to provide definitive guidance for optimizing endo-urological stone management [10]. Aims and Objectives Aim of the Study To evaluate and compare the clinical outcomes and overall safety of intracorporeal pneumatic lithotripsy versus Holmium:YAG laser lithotripsy in the management of ureteric stone disease [9, 10]. Objectives of the Study Primary Objectives: To assess and compare the complete stone clearance (stone-free rate) between pneumatic lithotripsy and Holmium:YAG laser lithotripsy [8, 10]. To compare the incidence and rate of stone retropulsion (proximal migration) during lithotripsy between both energy modalities [6, 8]. To evaluate and compare intraoperative complications, such as mucosal injury, bleeding, or ureteral perforation [7, 9]. To record and compare postoperative complications, including fever, gross hematuria, postoperative pain. Secondary Objectives: To compare procedural metrics, including stone fragmentation time and total operative duration between both groups [8, 10]. To determine the retreatment rate and the requirement for auxiliary procedures (such as Dormia basket extraction or Retrograde Intrarenal Surgery - RIRS) [8, 9]. To evaluate duration of hospital stay, timing of Double-J (DJ) stent removal, and long-term follow-up outcomes (including post-procedural ureteric stricture formation up to 6 months) [9, 10].

Study Design and Setting This was a prospective, observational randomized controlled study conducted in the Department of Urology at Chettinad Hospital and Research Institute (Kelambakkam, Kanchipuram District, Tamil Nadu, India) over a duration of 1.5 years between January 2024 and May 2025 [9, 10]. The study protocol was reviewed and approved by the Institutional Human Ethics Committee (CARE IHEC-I Approval Ref No: IHEC-I/3053/24) [9]. Written informed consent was obtained from all participants prior to enrollment [9, 10]. Patient Selection Criteria Inclusion Criteria: Patients of either sex aged 18 years or older [9]. Patients with radiologically documented ureteric stone disease suitable for ureteroscopic intervention [8, 9]. Exclusion Criteria: • Patients with anatomical abnormalities of the urinary tract [9]. • Patients with active urinary tract infection (UTI) [9]. • Pregnant women [9]. • Patients with uncorrected coagulopathy [9]. • Patients presenting with acute renal failure [9]. Sample Size Calculation and Randomization Based on key success rates from previous comparative literature [8], the sample size was calculated assuming a Type I error (alpha) of 0.05, statistical power of 80%, and standard deviation of 1.5 [9]. The required sample size was calculated as 44 patients per group, which was rounded up to 50 patients per arm to account for potential dropouts, resulting in a total sample size of 100 subjects [8, 9]. Participants were allocated in a 1:1 ratio into two intervention groups using a computer-generated randomization method [8, 9]. Group 1 (Pneumatic Lithotripsy - PL): 50 patients managed with pneumatic/ballistic lithotripsy [5, 8]. Group 2 (Holmium Laser Lithotripsy - LL): 50 patients managed with Holmium:YAG laser lithotripsy [4, 8]. Preoperative Evaluation All enrolled participants underwent detailed baseline clinical and diagnostic workups [9, 10]:
• Clinical Parameters: Detailed history, demographic details (age, sex, BMI), presenting symptoms, and co-morbidities [9, 10].
• Laboratory Investigations: Complete blood count (CBC), serum creatinine, coagulation profile (PT/INR, APTT), routine and microscopic urine analysis, and urine culture/sensitivity testing [9, 10].
• Radiological Evaluation: Ultrasonography KUB and Plain/Contrast Non-Contrast Computed Tomography (NCCT) KUB to determine exact stone size, location, stone attenuation density in Hounsfield Units (HU), and degree of hydronephrosis [8, 9, 10]. Surgical Procedure and Lithotripsy Techniques All surgical procedures were performed under General Anesthesia with patients in the lithotomy position. Prophylactic IV antibiotics were administered upon induction. Cystoscopy was initially conducted, and lower ureteric balloon dilatation over a 0.035-inch guidewire was carried out as needed. A safety guidewire was maintained throughout. Semi-rigid ureteroscopes (8/9.8 Fr or 6/7.5 Fr dual channel, Richard Wolf, Germany) were introduced based on ureteric caliber. Pneumatic Lithotripsy Protocol (Group 1): Utilized the Swiss LithoClast® Master and LithoClast® 2 system (EMS, Nyon, Switzerland) with probe diameters ranging from 0.8 to 1.2 mm [5]. Parameters were maintained at an energy setting of 70–90% and frequency of 7–9 Hz activated at 2.5 atm [5]. Probes were applied directly against the stone using single-shot or continuous pulse bursts until fragments were reduced to <2 mm or extractable sizes [5, 8]. Holmium Laser Protocol (Group 2): Utilized the 120W Lumenis Pulse™ laser system with MOSES™ technology operating at 2100 nm [4, 7]. A 365 µm fiber was positioned extending at least 2 mm beyond the scope tip and maintained 1 mm from the urothelium [4, 7]. Stone fragmentation was performed at 1.2–1.6 J energy and 10–15 Hz frequency, while stone dusting was executed at 0.8–1.0 J [9]. In all patients, 5/26 Fr Double-J (DJ) stents were placed under fluoroscopic guidance (IITV) [9]. Foley catheter drainage was maintained for 24 hours post-procedure. Patients were discharged on postoperative day 1 or 2 with oral antibiotics [9]. Follow-Up Schedule and Statistical Analysis Follow-up evaluations were systematically scheduled at the 1st week, 2nd week (for DJ stent removal and stone clearance verification), 3rd month, and 6th month postoperatively using USG KUB, X-ray KUB, and serum biochemistry [9, 10]. Data were statistically analyzed using SPSS software (Version 20.0/22.0, IBM Corp., Chicago, IL, USA) [9, 10]. Continuous variables were reported as Mean ± Standard Deviation and compared using Student's t-test / ANOVA [9, 10]. Categorical variables were presented as frequencies (%) and analyzed using the Chi-square test [9, 10]. Normality was tested via the Kolmogorov-Smirnov test [9, 10]. A p-value < 0.05 was considered statistically significant [9, 10].

A total of 100 subjects with ureteric stone disease completed the study protocol and were analyzed across two equal intervention groups (Group 1: Pneumatic Lithotripsy, n=50; Group 2: Holmium:YAG Laser Lithotripsy, n=50) [9, 10]. 1. Baseline Socio-Demographic and Clinical Characteristics Both study groups were well-matched at baseline with no statistically significant differences in age, gender distribution, stone laterality, mean stone size, stone attenuation density (Hounsfield Units), or preoperative laboratory parameters (Table 1) [8, 9, 10]. Parameter Group 1 (Pneumatic) Group 2 (Ho:YAG Laser) p-value Mean Age (Years) 48.60 ± 15.11 45.84 ± 14.88 0.36 (NS) Gender (Male / Female) 34 (68%) / 16 (32%) 37 (74%) / 13 (26%) 0.50 (NS) Stone Laterality (Right / Left) 26 (52%) / 24 (48%) 27 (54%) / 23 (46%) 0.84 (NS) Stone Location (Upper / Mid / Lower) 20 (40%) / 16 (32%) / 14 (28%) 16 (32%) / 18 (36%) / 16 (32%) 0.68 (NS) Mean Stone Size (mm) 9.69 ± 2.29 9.71 ± 2.01 0.95 (NS) Mean Stone Density (HU) 1168.84 ± 144.73 1141.98 ± 182.91 0.42 (NS) Preoperative Hemoglobin (g/dL) 12.99 ± 1.72 12.42 ± 2.07 0.14 (NS) Total Leucocyte Count (/mm³) 8245.10 ± 2137.75 7935.31 ± 2244.45 0.48 (NS) Preoperative Serum Creatinine (mg/dL) 1.19 ± 0.65 1.14 ± 0.45 0.65 (NS) 2. Intraoperative Outcomes and Stone Fragmentation Profile While mean stone fragmentation time (5.47 ± 2.60 min in PL vs. 4.83 ± 1.91 min in LL; p=0.16) and total operative duration (48.06 ± 14.81 min in PL vs. 51.54 ± 9.95 min in LL; p=0.71) were comparable between groups, stone retropulsion was significantly higher in the Pneumatic Lithotripsy group (34% vs. 16% in Laser group; p=0.03) [5, 8, 10]. Consequently, additional auxiliary procedures (such as flexible ureteroscopy / RIRS) were required in 32% of PL cases compared to 18% of LL cases (Table 2) [8, 10]. Intraoperative Variable Group 1 (Pneumatic) Group 2 (Ho:YAG Laser) p-value Stone Fragmentation Time (min) 5.47 ± 2.60 4.83 ± 1.91 0.16 (NS) Mean Operative Time - MOT (min) 48.06 ± 14.81 51.54 ± 9.95 0.71 (NS) Stone Retropulsion Rate (%) 17 (34%) 8 (16%) 0.03 (Sig) Intraoperative Mucosal Injury (%) 6 (12%) 9 (18%) 0.40 (NS) Ureteral Perforation Rate (%) 0 (0%) 0 (0%) 1.00 (NS) Auxiliary Procedures Needed (%) 16 (32%) 9 (18%) 0.42 (NS) • Dormia Basket Alone 1 (2%) 1 (2%) — • Dormia Basket + RIRS 2 (4%) 1 (2%) — • RIRS Alone 13 (26%) 7 (14%) — Immediate Stone-Free Rate (%) 48 (96%) 50 (100%) 0.36 (NS) 3. Postoperative Complications, Hospital Stay, and Follow-Up Immediate postoperative gross hematuria was significantly more frequent in the Holmium Laser group (34% vs. 12% in Pneumatic group; p=0.009), attributable to the dusting energy and mucosal contact [4, 10]. Postoperative fever occurred in 16% of PL vs. 8% of LL patients (p=0.21) [9, 10]. Visual Analog Scale (VAS) pain scores (3.06 ± 0.87 vs. 2.94 ± 0.96; p=0.51) and mean hospital stay (37.98 ± 7.61 hrs vs. 36.66 ± 8.56 hrs; p=0.41) did not differ significantly [9, 10]. Complete stone-free clearance at 2 weeks reached 96% in Group 1 and 98% in Group 2 (p=0.55) [8, 10]. At 6-month follow-up, a single patient in the Holmium Laser group developed a late ureteric stricture (2% vs. 0% in PL; p=0.31) (Table 3) [9, 10]. Postoperative Parameter Group 1 (Pneumatic) Group 2 (Ho:YAG Laser) p-value Gross Hematuria (%) 6 (12%) 17 (34%) 0.009 (Sig) Immediate Postoperative Fever (%) 8 (16%) 4 (8%) 0.21 (NS) VAS Pain Score (0–10) 3.06 ± 0.87 2.94 ± 0.96 0.51 (NS) Clavien-Dindo Complication Grade Grade 2 Grade 2 1.00 (NS) Mean Hospital Stay (Hours) 37.98 ± 7.61 36.66 ± 8.56 0.41 (NS) Double-J Stent Removal (Days) 14.28 ± 1.38 15.58 ± 3.41 0.01 (Sig) 1st Week Residual Stones (%) 5 (10%) 7 (14%) 0.53 (NS) 2nd Week Residual Stones (%) 2 (4%) 1 (2%) 0.55 (NS) 3rd Month Pelvicalyceal Dilatation (%) 0 (0%) 1 (2%) 0.31 (NS) 6th Month Ureteric Stricture Rate (%) 0 (0%) 1 (2%) 0.31 (NS) Summary of Findings: Pneumatic and Holmium:YAG laser lithotripsy both achieve excellent immediate stone-free status (>96%) [ 8, 10]. However, Holmium Laser Lithotripsy demonstrates a statistically significant reduction in stone retropulsion (16% vs. 34%, p=0.03), decreasing the reliance on auxiliary procedures [6, 8, 10]. Conversely, Holmium Laser was associated with a higher transient incidence of post-procedural gross hematuria (34% vs. 12%, p=0.009) [4, 10].

The management of ureteric stone disease has undergone a transformative evolution with the advent of advanced endoscopic instrumentation and intracorporeal lithotripsy modalities [2, 3]. The primary objective of ureteroscopic lithotripsy is to achieve complete stone clearance with minimal morbidity and low complication rates [3, 10]. In the present prospective randomized controlled trial, we compared the efficacy and safety of intracorporeal pneumatic lithotripsy versus Holmium:YAG laser lithotripsy in 100 patients [9, 10]. Our demographic analysis revealed a mean patient age of 48.60 years in the pneumatic group and 45.84 years in the laser group, with a male predominance (71% overall), aligning closely with international epidemiological data and previous comparative investigations [1, 8, 10]. Regarding stone characteristics, baseline parameters including mean stone size (~9.7 mm) and stone attenuation density (~1150 HU) were comparable between the two arms [9, 10]. Our stone fragmentation times (5.47 min vs. 4.83 min) and total operative durations (48.06 min vs. 51.54 min) showed no statistically significant differences, demonstrating that modern pneumatic lithotripters and high-power Holmium lasers offer comparable mechanical efficiency during stone breakdown [5, 8, 10]. A critical finding in our study was the significantly higher rate of stone retropulsion observed in the pneumatic lithotripsy group (34%) compared to the Holmium laser group (16%; p=0.03) [5, 6, 8]. Pneumatic lithotripsy operates via a ballistic projectile mechanism that imparts kinetic energy upon impact, frequently causing proximal stone migration, particularly in upper ureteric calculi [5]. Conversely, the photothermal mechanism of the Ho:YAG laser efficiently vaporizes and dusts stones with minimal mechanical kickback, thereby reducing stone migration [4, 7]. This higher retropulsion rate in the pneumatic group necessitated a greater need for auxiliary procedures such as flexible ureteroscopy (RIRS) and Dormia basket retrieval (32% vs. 18%) [8, 10]. Our findings corroborate those of prior multi-center trials which reported significantly lower retropulsion and reduced secondary intervention requirements with laser lithotripsy [8, 10]. In terms of safety and complications, both modalities exhibited excellent profiles with zero ureteral perforations recorded [9, 10]. Intraoperative mucosal abrasions were comparable (12% in PL vs. 18% in LL; p=0.40) [9, 10]. Interestingly, immediate postoperative gross hematuria was significantly more prevalent in the Holmium laser group (34% vs. 12%; p=0.009), which can be attributed to the thermal energy dispersion and increased mucosal hyperaemia associated with laser dusting in narrow ureteric lumens [4, 10]. Postoperative fever, VAS pain scores, Clavien-Dindo complication grades (Grade 2), and hospital stays (~37 hours) showed no statistically significant differences [9, 10]. Long-term follow-up at 6 months revealed a rare ureteric stricture in only one patient (2%) in the laser group, with none reported in the pneumatic group (p=0.31) [9, 10].

This prospective randomized controlled study evaluated 100 patients undergoing ureteroscopic lithotripsy for ureteric stone disease comparing intracorporeal pneumatic lithotripsy and Holmium:YAG laser lithotripsy [8, 9, 10]. Both energy sources demonstrated high efficacy, achieving immediate stone-free rates of 96% in the pneumatic group and 100% in the laser group [8, 10]. Procedural times and overall hospitalization were comparable [9, 10]. However, Holmium:YAG laser lithotripsy demonstrated a statistically significant advantage in minimizing stone retropulsion and reducing the need for secondary auxiliary stone retrieval procedures [4, 8]. While pneumatic lithotripsy remains an affordable, highly dependable, and robust option—particularly in resource-constrained settings—Holmium laser lithotripsy offers superior stone-free kinetics and reduced migration for ureteric calculi [4, 5, 8]. Therefore, Holmium laser lithotripsy is recommended for optimal ureteroscopic management where available, balancing high efficacy against equipment cost and technical expertise requirements [4, 10]. Conclusion Summary: Final Clinical Takeaway: Both pneumatic and Holmium laser lithotripters are highly effective for ureteric stones. Holmium laser lithotripsy provides superior resistance against stone retropulsion and higher immediate stone clearance, whereas pneumatic lithotripsy offers excellent cost-effectiveness and durability [4, 5, 8, 10]

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