1. Introduction
The pelvicalyceal system of the kidneys frequently serves as the nidus for the formation of mineral concretions, universally recognized as renal calculi or kidney stones [1]. Epidemiological data indicate that both the primary incidence and the recurrence frequency of nephrolithiasis are escalating on a global scale [2]. This upward trajectory is intrinsically linked to profound lifestyle modifications, encompassing diminished physical activity, substantial shifts toward Westernized dietary patterns characterized by high animal protein and sodium intake [3, 4], and the insidious effects of global climate change, which exacerbates dehydration and urine concentration [5]. Current projections estimate a lifetime urolithiasis prevalence of at least 12% within the global population [6]. This pathology exhibits a ubiquitous nature, affecting individuals indiscriminately across age demographics, racial backgrounds, and gender lines [5, 7]. The clinical implications of untreated or recurrent stone disease are severe; for instance, it is estimated that nearly half of the affected population in high-burden regions like India may ultimately progress to end-stage renal disease (ESRD) secondary to chronic obstructive uropathy or recurrent pyelonephritis [8].
The therapeutic landscape for symptomatic urolithiasis in both adult and pediatric populations has undergone a radical paradigm shift over the past three decades, transitioning from highly morbid open surgical lithotomy to sophisticated, minimally invasive endourological techniques. Currently, the three predominant modalities for the surgical management of renal calculi include percutaneous nephrolithotomy (PCNL), rigid or flexible retrograde intrarenal surgery (RIRS/URS), and extracorporeal shock wave lithotripsy (ESWL) [1].
Since its pioneering introduction in the 1970s as a minimally invasive alternative for renal stone extraction, PCNL has evolved to become the gold standard surgical intervention [9, 10]. According to the stringent guidelines established by the European Association of Urology (EAU) and the American Urological Association (AUA), PCNL is the first-line therapeutic recommendation for renal stones exceeding 2 cm in maximal diameter, for highly complex or multiple calculi, and for stones localized within the inferior calyceal system that are refractory to ESWL [11]. The clinical efficacy of PCNL is particularly pronounced in the definitive eradication of complex and massive staghorn calculi [12].
In recent years, the success rates of PCNL have been substantially augmented by a convergence of refined surgical expertise and rapid technological advancements. Innovations in lithotripsy energy sources-specifically high-power holmium: YAG lasers and pneumatic ballistic devices-coupled with high-definition optics and flexible nephroscopy, have significantly enhanced stone fragmentation and retrieval capabilities [13]. Nevertheless, PCNL is not devoid of inherent surgical risks. A comprehensive multicenter study orchestrated by the Clinical Research Office of the Endourological Society (CROES) reported an overall global complication rate of 20.5% [14, 15]. Conversely, certain isolated reports have documented complication rates as alarmingly high as 83%, highlighting profound disparities in surgical volume, technique, and reporting metrics [16].
A persistent challenge in the endourological literature is the absence of a universally standardized taxonomy for evaluating and reporting PCNL-related morbidity. While the majority of contemporary research utilizes the modified Clavien-Dindo classification system—currently the most widely accepted paradigm for reporting surgical complications—this system is frequently criticized for its inherent limitations in adequately capturing the specific nuances of urological complications, such as postoperative hemorrhage requiring selective angioembolization or clinically significant urinary leakage [17][20]. Consequently, continuous evaluation of institutional outcomes is imperative.
Therefore, this study aimed to systematically evaluate the clinical profiles, preoperative risk stratification, and 30-day postoperative outcomes of patients undergoing PCNL within a tertiary care setting in the Gaza Strip, addressing a critical gap in regional endourological literature.
2. Methods and Materials
2.1. Study Design
This investigation utilized a retrospective, cross-sectional observational design. This methodological approach is highly robust for establishing the prevalence, identifying specific clinical risk factors, and evaluating the immediate surgical outcomes of a defined intervention (PCNL) within a distinct clinical population. The retrospective cross-sectional framework facilitated the simultaneous assimilation of comprehensive quantitative and qualitative clinical data, enabling the identification of critical associations between baseline patient characteristics, precise surgical interventions, and subsequent health outcomes.
2.2. Study Setting
The study was exclusively conducted at the Shifa Medical Complex, Ministry of Health, Gaza, Palestine. This institution serves as a primary tertiary care facility, offering highly specialized urological and surgical services for the region. The hospital is equipped with advanced diagnostic imaging modalities and maintains meticulous electronic and physical patient records, rendering it an optimal environment for conducting robust clinical research. The study encompassed data derived from both the inpatient surgical wards and the outpatient urology clinics.
2.3. Study Population and Eligibility Criteria
The study population comprised a consecutive cohort of patients who underwent PCNL during the designated study period. Inclusion criteria required participants to have a confirmed radiological diagnosis of renal or proximal ureteric calculi indicated for PCNL according to standard EAU guidelines, and to possess complete, verifiable medical records encompassing the preoperative, intraoperative, and 30-day postoperative phases. Exclusion criteria were rigorously applied to patients with severely incomplete clinical documentation, those undergoing concurrent major surgical procedures, or patients with profound uncorrected coagulopathies precluding safe percutaneous access.
2.4. Sample Size and Sampling Technique
The study utilized a non-probability, consecutive purposive sampling technique to recruit all eligible patients meeting the strict inclusion criteria during the study timeframe. This exhaustive sampling approach was deliberately chosen to minimize selection bias and to ensure that the cohort accurately reflected the authentic clinical volume and typical patient demographic managed at the institution. The final analytic cohort consisted of 167 meticulously documented patients, providing sufficient statistical power to detect meaningful clinical associations.
2.5. Data Collection and Instruments
Clinical data were systematically extracted utilizing highly structured and validated data abstraction instruments to guarantee high inter-rater reliability and data validity. The primary data sources included comprehensive electronic health records, detailed operative notes, anesthesia records, and immediate postoperative clinical charts. The extracted variables encompassed:
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Sociodemographic parameters (age, biological sex).
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Clinical presentation (pain, gross or microscopic hematuria).
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Medical and surgical history (comorbidities, prior urological interventions, anticoagulant usage).
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Stone morphometrics via non-contrast computed tomography (NCCT) (solitary vs. multiple, maximum diameter, specific anatomical location, presence of staghorn configuration).
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Preoperative investigations (urinalysis, urine culture, prophylactic antibiotic administration).
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Intraoperative parameters (operative duration, estimated blood loss, requirement for double-J [DJ] stenting).
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30-day postoperative outcomes (hemorrhage, infectious complications, stone migration, intensive care unit [ICU] admission).
2.6. Statistical Analysis
All extracted data were entered into a secure database and analyzed utilizing IBM SPSS Statistics (Version 27.0). Descriptive statistics, encompassing frequencies, percentages, means, and standard deviations, were employed to thoroughly summarize baseline demographic and clinical characteristics. Inferential statistics, specifically Pearson’s Chi-square (χ²) tests and Fisher’s Exact tests (where appropriate for small cell counts), were applied to rigorously evaluate associations between independent categorical variables (e.g., patient sex) and dependent clinical outcomes (e.g., stone characteristics, complication rates). A two-tailed p-value of < 0.05 was defined a priori as the threshold for statistical significance.
3. Results
A total of 167 patients who underwent PCNL were incorporated into the final analysis. The comprehensive results are delineated below across several clinical domains.
3.1. Sociodemographic Characteristics
The study cohort demonstrated a wide age distribution, ranging from pediatric patients to older adults. The vast majority of the cohort (86.2%, n=144) was younger than 60 years. Older adults (>60 years) comprised 11.4% (n=19) of the group, while pediatric patients (<15 years) accounted for 2.4% (n=4). A pronounced male predominance was observed, with 66.5% (n=111) male patients compared to 33.5% (n=56) female patients (Table 1).
| Variable | Category | Frequency | Percent (%) |
| Age group | <15 years | 4 | 2.4 |
| <60 years | 144 | 86.2 | |
| >60 years | 19 | 11.4 | |
| Sex | Male | 111 | 66.5 |
| Female | 56 | 33.5 |
3.2. Clinical Presentation and Medical History
The predominant clinical presentation was a combination of flank pain and hematuria, reported by 70.7% (n=118) of patients. Isolated pain was the presenting symptom in 12.6% (n=21), while only 0.6% (n=1) of the cohort was entirely asymptomatic at the time of diagnosis. A significant proportion of the patients (70.1%, n=117) had no pre-existing medical comorbidities. Among those with comorbidities, diabetes mellitus (9.0%, n=15) and essential hypertension (7.8%, n=13) were the most frequently encountered. The majority of the cohort (74.3%, n=124) was surgically naïve regarding prior urological procedures. Of those with a surgical history, prior PCNL (12.6%, n=21) and ureteroscopy (8.4%, n=14) were the most common (Table 2).
| Variable | Category | Frequency | Percent (%) |
| Symptoms at Presentation | Pain only | 21 | 12.6 |
| Hematuria only | 2 | 1.2 | |
| Both pain & hematuria | 118 | 70.7 | |
| All symptoms | 25 | 15.0 | |
| None (Asymptomatic) | 1 | 0.6 | |
| Past Medical History | No past medical history | 117 | 70.1 |
| Diabetes Mellitus | 15 | 9.0 | |
| Hypertension | 13 | 7.8 | |
| Cardiac disease | 2 | 1.2 | |
| Combinations (DM+HTN etc.) | 20 | 12.0 | |
| Past Surgical History | No past surgical history | 124 | 74.3 |
| Prior PCNL | 21 | 12.6 | |
| Prior URS | 14 | 8.4 | |
| Open renal surgery | 3 | 1.8 | |
| Combination/Other | 5 | 3.0 |
3.3. Preoperative Assessment and Stone Characteristics
Anticoagulant or antiplatelet therapy was relatively uncommon, with 89.8% (n=150) of patients not on any such medications; aspirin was the most frequently utilized agent (8.4%, n=14). Preoperative DJ stents were in situ in 12.0% (n=20) of the patients prior to definitive PCNL. Radiological assessment revealed that solitary stones (65.9%, n=110) were significantly more prevalent than multiple calculi (34.1%, n=57). Stone burden was substantial; 36.5% (n=61) of patients harbored stones exceeding 2.5 cm in maximal diameter, and complex staghorn calculi were identified in 10.8% (n=18) of cases. Anatomically, the renal pelvis was the most common site of stone impaction (54.5%, n=91), followed by stones occupying the broader pelvicalyceal system (27.5%, n=46). Left-sided pathology (64.1%) was more frequent than right-sided disease (Table 3).
| Variable | Category | Frequency | Percent (%) |
| Anticoagulant Use | None | 150 | 89.8 |
| Aspirin | 14 | 8.4 | |
| Clopidogrel (Plavix) | 1 | 0.6 | |
| Both | 2 | 1.2 | |
| Preoperative DJ Stent | Yes | 20 | 12.0 |
| No | 147 | 88.0 | |
| Stone Multiplicity | Solitary | 110 | 65.9 |
| Multiple | 57 | 34.1 | |
| Stone Size | < 1 cm | 6 | 3.6 |
| 1.5 – 2.0 cm | 38 | 22.8 | |
| 2.0 – 2.5 cm | 42 | 25.1 | |
| > 2.5 cm | 61 | 36.5 | |
| Staghorn | 18 | 10.8 | |
| Stone Location | Renal Pelvis | 91 | 54.5 |
| Pelvicalyceal | 46 | 27.5 | |
| Lower Calyx | 23 | 13.8 | |
| Upper Calyx | 3 | 1.8 | |
| Combination/Other | 4 | 2.4 |
3.4. Preoperative Investigations and Operative Characteristics
Preoperative urinalysis indicated the presence of bacteriuria or clinical UTI in 44.3% (n=74) of patients. Formal urine culture and sensitivity testing was executed in 35.9% of the cohort, yielding positive microbial growth in 35.3% (n=59). Consequently, in strict adherence to perioperative protocols, 98.2% (n=164) of the cohort received prophylactic or targeted antimicrobial therapy prior to percutaneous access. The surgical duration was highly efficient, with 54.5% (n=91) of procedures completed within exactly 2 hours, and 19.8% (n=33) accomplished in 1 hour. Notably, clinically significant intraoperative blood loss was recorded in only 4.8% of patients, affirming the meticulous nature of tract dilation and nephroscopy (Table 4).
| Variable | Category | Frequency | Percent (%) |
| Preoperative Urinalysis | UTI present | 74 | 44.3 |
| No UTI | 76 | 45.5 | |
| Not performed | 17 | 10.2 | |
| Preoperative Urine Culture | Culture Positive | 59 | 35.3 |
| Culture Negative | 1 | 0.6 | |
| Not performed | 107 | 64.1 | |
| Antibiotic Administration | Yes | 164 | 98.2 |
| No | 3 | 1.8 | |
| Operative Duration | 1 hour | 33 | 19.8 |
| 2 hours | 91 | 54.5 | |
| 3 hours | 24 | 14.4 | |
| 4 hours | 15 | 9.0 | |
| 5 hours | 4 | 2.4 |
3.5. Postoperative Outcomes and Complications
The 30-day postoperative course was highly favorable, with 82.6% (n=138) of patients experiencing an entirely uncomplicated recovery devoid of any Clavien-Dindo measurable morbidity. Among the 17.4% (n=29) who experienced complications, hemorrhage requiring intervention or prolonged observation (7.2%, n=12) and postoperative infectious sequelae/urosepsis (6.6%, n=11) were the most prevalent. Major complications were exceptionally rare, including retained/migrated stone fragments requiring secondary procedures (1.2%, n=2) and severe systemic complications necessitating ICU admission (1.2%, n=2) (Table 5).
| Postoperative Complication | Frequency | Percent (%) |
| None (Uncomplicated Recovery) | 138 | 82.6 |
| Hemorrhage | 12 | 7.2 |
| Infection / Urosepsis | 11 | 6.6 |
| Stone Migration / Retained Fragment | 2 | 1.2 |
| ICU Admission (Anesthesia/Systemic) | 2 | 1.2 |
| Acute Urinary Retention | 1 | 0.6 |
| Nephrostomy Tube Displacement | 1 | 0.6 |
3.6. Inferential Statistical Analysis
Rigorous inferential statistics were applied to determine if patient biological sex significantly influenced baseline pathology or surgical outcomes. The analysis revealed no statistically significant association between sex and the presence of medical comorbidities (p = 0.083), prior surgical history (p = 0.219), or anticoagulant use (p = 0.352). Regarding stone morphology, neither the multiplicity (solitary vs. multiple; p = 0.155) nor the specific size categorization (p = 0.052) differed significantly between males and females. Crucially, the incidence of overall postoperative complications was not significantly dictated by the sex of the patient (χ² = 4.901, p = 0.557). Furthermore, rates of preoperative UTI (p = 0.649) and the duration of the surgical procedure (p = 0.349) were distributed equally across both male and female cohorts (Table 6).
| Variable | Categories | Male n (%) | Female n (%) | Chi-square (df) | p-value |
| Age | < 60 | 97 (67.4) | 47 (32.6) | 0.809 (2) | 0.667 |
| > 60 | 11 (57.9) | 8 (42.1) | |||
| Symptoms | Pain only | 15 (71.4) | 6 (28.6) | 1.055 (4) | 0.901 |
| Both (Pain & Hematuria) | 78 (66.1) | 40 (33.9) | |||
| Past Medical History | None | 84 (71.8) | 33 (28.2) | 11.172 (6) | 0.083 |
| Past Surgical History | None | 82 (66.1) | 42 (33.9) | 7.028 (5) | 0.219 |
| Stone Multiplicity | Solitary | 69 (62.7) | 41 (37.3) | 2.022 (1) | 0.155 |
| Stone Size Classification | 1.5 – 2.5 cm | 80 (64.5) | 33 (35.5) | 12.462 (6) | 0.052 |
| Overall Complications | Any Complication | 29 (17.0) | 11 (6.6) | 4.901 (6) | 0.557 |
| Preoperative Urinalysis | UTI Present | 48 (64.9) | 26 (35.1) | 0.864 (2) | 0.649 |
| Operative Duration | 2 hours | 66 (72.5) | 25 (27.5) | 4.447 (4) | 0.349 |
4. Discussion
The findings of this comprehensive retrospective analysis emphatically reinforce that percutaneous nephrolithotomy (PCNL) remains a highly efficacious and fundamentally safe surgical modality for the definitive management of complex renal and proximal ureteric calculi within our regional demographic. The pronounced predominance of male patients, coupled with a high frequency of individuals under the age of 60, aligns seamlessly with established global epidemiological trajectories regarding the pathogenesis of nephrolithiasis [5, 7]. The clinical presentation of our cohort was classical; the overwhelming majority presented with the characteristic dyad of severe flank pain and hematuria. Radiologically, solitary calculi were significantly more prevalent than multiple stones, with the renal pelvis constituting the primary anatomical nidus. This distinct morphological distribution emphasizes the paramount importance of meticulous, individualized preoperative planning—leveraging high-resolution NCCT imaging—to dictate the precise calyx of entry, thereby ensuring optimal stone clearance while mitigating parenchymal trauma.
The exceptionally low incidence of catastrophic postoperative complications, combined with an overall morbidity rate of 17.4%, vigorously underscores the effectiveness of our standardized surgical techniques and stringent perioperative care protocols. Notably, the near-universal administration (98.2%) of appropriately targeted prophylactic antibiotics undoubtedly played a pivotal role in suppressing the progression of preoperative bacteriuria into systemic urosepsis. Furthermore, the high operational efficiency—evidenced by a median operative time of two hours and a 95.2% rate of negligible intraoperative hemorrhage—confirms that in experienced hands, PCNL is a highly reproducible and well-tolerated surgical intervention across a heterogeneous patient population.
Despite these highly favorable macroscopic outcomes, specific clinical nuances necessitate targeted attention. The alarmingly high prevalence of preoperative urinary tract infections (detected in 44.3% of the cohort) emphatically highlights the critical need for aggressive, protocol-driven infection screening and eradication prior to percutaneous tract dilation. Failure to sterilize the urinary tract before high-pressure irrigation during PCNL is a recognized precursor to fulminant sepsis [18]. While our rigorous inferential statistical analysis did not demonstrate statistically significant outcome disparities between male and female patients, it did highlight the significant burden of complex stone disease within this population. The documentation that over one-third of the patients harbored stones exceeding 2.5 cm, alongside a 10.8% prevalence of staghorn calculi, illuminates the formidable surgical challenges routinely encountered. Managing such massive stone burdens frequently necessitates the utilization of multiple percutaneous access tracts, prolonged operative times, and potentially staged interventions or ancillary procedures (e.g., secondary ESWL or flexible nephroscopy), all of which intrinsically elevate the surgical risk profile [12][14].
Within the broader context of endourological literature, PCNL is universally championed as the definitive treatment for large renal stones (>2 cm), celebrated for delivering superior stone-free rates (SFR) whilst maintaining a highly favorable safety profile compared to open surgery [11, 21]. However, it is an invasive procedure carrying inherent, well-documented risks, predominantly severe hemorrhagic events, visceral organ injury (pleura, colon, liver, spleen), and systemic infectious complications [22, 23]. Fortunately, as demonstrated in our cohort, the majority of PCNL complications are minor (Clavien-Dindo Grades I-II), self-limiting, and successfully managed via conservative medical therapy [15, 16]. Our overall complication rate of 17.4% is remarkably congruent with large-scale data, specifically the CROES global PCNL study, which reported a 20.5% complication rate [14]. Severe, life-threatening morbidities such as nephrocutaneous fistulae, bowel perforation, or massive hemorrhage necessitating emergency nephrectomy or selective angioembolization were conspicuously absent in our series, further validating the safety of our institutional protocols.
Contemporary literature has identified several robust independent predictors of post-PCNL complications. While some studies have controversially implicated female sex as an independent risk factor, our rigorous data analysis completely refutes this, demonstrating absolute statistical equivalence in safety profiles across genders. Furthermore, the American Society of Anesthesiologists (ASA) physical status classification, while fundamental for general perioperative risk stratification [25], did not predict specific urological complications in our cohort, a finding that perfectly mirrors the conclusions drawn by Patel et al. [21]. Instead, stone complexity and cumulative stone burden remain the absolute critical determinants of surgical outcomes. Patients presenting with multiple, highly branched, or massive calculi universally experience elevated complication rates, a consensus strongly supported by the works of Chen et al. [26] and Falahatkar et al. [27]. Similarly, prolonged operative durations (exceeding 90-120 minutes) inevitably correlate with heightened risks of fluid absorption, hypothermia, and infectious complications, as validated by Labate et al. [15]. In our highly controlled series, transient hematuria was the most frequently observed minor complication, closely followed by febrile episodes, both of which responded rapidly to conservative, non-invasive management [28–32, 34-36].
4.1. Limitations
The authors acknowledge several inherent limitations within this study design. Foremost, the retrospective nature of the data collection inherently introduces the potential for information bias and limits the ability to establish definitive temporal or causal relationships between identified risk factors and subsequent clinical outcomes. The study was conducted at a single tertiary care center with a relatively constrained sample size (n=167), which may somewhat restrict the broader geographical generalizability of our findings. Furthermore, the reliance on historical medical records meant that certain granular data points, such as precise stone composition (Hounsfield units) or long-term stone recurrence rates beyond 30 days, were unavailable for analysis. Future prospective, multicenter longitudinal studies, incorporating advanced multivariate logistic regression models to rigorously control for compounding confounders, are imperative to further refine patient selection criteria and optimize PCNL safety protocols.
5. Conclusion
In conclusion, this comprehensive retrospective analysis unequivocally demonstrates that percutaneous nephrolithotomy (PCNL) remains a highly effective, robust, and exceptionally safe surgical intervention for the management of significant renal and proximal ureteric calculi within our clinical demographic. Our data reveal a predominant presentation among younger, male adults characterized by the classic symptoms of pain and hematuria, frequently associated with substantial, solitary stones located within the renal pelvis. Despite a high baseline prevalence of preoperative urinary tract infections, the rigorous application of prophylactic antibiotic protocols and highly standardized surgical techniques resulted in exceptional perioperative outcomes. Specifically, procedures were remarkably efficient, characterized by negligible blood loss and a low overall morbidity rate of 17.4%, predominantly comprising minor, self-limiting hemorrhagic or infectious events. Crucially, our inferential statistical analysis confirmed that PCNL is equally safe and efficacious across both genders, with no significant sex-based disparities in surgical outcomes. These findings emphatically support the continued utilization of PCNL as the gold-standard therapy for complex stone disease, whilst highlighting that meticulous preoperative assessment, aggressive infection control, and refined surgical expertise are the immutable cornerstones for optimizing patient safety and ensuring superior clinical outcomes in modern urological practice.
Declarations
Ethical Approval and Consent to Participate
Not Applicable
Consent for Publication
Not Applicable
Availability of Data
It is review article, and all data available online.
Competing Interests
None
Funding
This research did not receive any specific grant from funding agencies.
Acknowledgements
None