Percutaneous nephrolithotomy (PCNL) has established itself as the gold standard for the management of large and complex renal calculi, especially those measuring over 2 cm in diameter or resistant to less invasive approaches such as extracorporeal shock wave lithotripsy (ESWL) and ureteroscopy [1]. Since its inception in the 1970s, Standard PCNL (S-PCNL) has traditionally utilized access tract sizes ranging from 24 to 30 French (Fr), allowing for efficient stone fragmentation and removal using rigid nephroscopes and energy devices like pneumatic or ultrasonic lithotripters [2]. However, this approach is not without drawbacks; S-PCNL is frequently associated with increased intraoperative blood loss, higher transfusion rates, and potential injury to the renal parenchyma, especially in anatomically complex or high-risk patients [3].

In response to these concerns, miniaturized PCNL techniques—collectively termed Mini-PCNL—have gained prominence in recent years. These methods employ reduced tract sizes (typically 14–20 Fr), leveraging advances in optics, mini-nephroscopes, and fine-caliber lithotripsy instruments to offer a less invasive yet effective alternative [4]. Evidence from comparative and retrospective studies has indicated that Mini-PCNL may provide several advantages over standard techniques, including decreased perioperative bleeding, shorter hospital stay, reduced postoperative pain, and a lower risk of complications, without compromising stone clearance efficacy [1, 3, 5]. Furthermore, ambulatory and tubeless variants of Mini-PCNL have shown promise in optimizing recovery time and healthcare resource utilization [5].

Despite these potential benefits, questions remain regarding Mini-PCNL’s efficacy in managing large stone burdens, where fragment retrieval through narrower tracts may be technically challenging. Additionally, there is concern that reduced instrumentation maneuverability might contribute to longer operative durations [2, 4].

Among the various factors influencing PCNL outcomes, perioperative blood loss remains a paramount concern. Excessive hemorrhage can compromise patient stability, necessitate blood transfusions, and prolong hospitalization. Tract size has been identified as a critical determinant of bleeding risk, with smaller access tracts likely contributing to reduced parenchymal disruption [3].

Against this backdrop, the present study was designed to systematically compare perioperative blood loss and surgical outcomes between Standard PCNL and Mini-PCNL techniques in patients undergoing renal stone surgery at a tertiary care center. Through this comparison, we aim to provide evidence-based insights into optimizing tract selection to balance surgical efficiency with patient safety.

By evaluating the impact of tract size on hemoglobin drop, estimated blood loss, transfusion needs, and perioperative complications, this study seeks to contribute evidence toward optimizing surgical approach selection, particularly in patients at risk for bleeding complications.

Study Design

A hospital-based prospective comparative observational study was conducted to evaluate the impact of tract size on perioperative blood loss in patients undergoing Standard PCNL (S-PCNL) and Mini-PCNL (M-PCNL).

Study Setting and Duration

The study was carried out in the Department of Urology at Government Medical College, Ramagundam, Telangana, over a period of 12 months, from January 2024 to December 2024.

Study Population

Patients aged 18–65 years undergoing PCNL for renal calculi >1.5 cm were considered eligible. All patients were admitted electively for PCNL under spinal or general anesthesia.

Inclusion Criteria

Patients aged between 18 and 65 years

Renal stones ≥1.5 cm in maximum dimension

ASA physical status I or II

Normal coagulation profile

Informed written consent provided

Exclusion Criteria

Patients with bleeding disorders or on anticoagulants

Solitary kidney

Active urinary tract infection

Previous renal surgery on the same side

Pregnancy

Sample Size

A total of 100 patients were recruited using purposive sampling. Patients were equally divided into two groups:

Group A: Standard PCNL (tract size 24–30 Fr), n = 50

Group B: Mini-PCNL (tract size 14–20 Fr), n = 50

Procedure

All procedures were performed by experienced urologists following standard aseptic protocols. Tract size selection was based on preoperative stone assessment and surgeon preference.

Preoperative Workup Included:

Complete blood count, renal function tests, urine culture

Imaging: Ultrasound KUB and NCCT

Informed written consent

Intraoperative Parameters Recorded:

Tract size and number of tracts

Operative time (skin incision to closure)

Intraoperative blood loss (estimated using suction volumes and gauze weight)

Postoperative Parameters Recorded:

Hemoglobin levels: preoperative and 24 hours postoperative

Hemoglobin drop (g/dL)

Blood transfusion requirement

Complications (graded using Clavien-Dindo classification)

Statistical Analysis

Data were entered into Microsoft Excel and analyzed using SPSS version 25.0. Descriptive statistics were expressed as mean ± standard deviation for continuous variables and as frequency and percentage for categorical variables.

Independent t-test was used to compare continuous variables between groups (e.g., hemoglobin drop, operative time).

Chi-square test was applied for categorical variables (e.g., blood transfusion requirement, complications).

A p-value of <0.05 was considered statistically significant.

Ethical Considerations

The study protocol was approved by the Institutional Ethics Committee of Government Medical College, Ramagundam. Written informed consent was obtained from all participants prior to inclusion in the study.

Baseline Characteristics

A total of 100 patients undergoing PCNL were included in the study, with 50 patients each in the Standard PCNL (S-PCNL) and Mini-PCNL (M-PCNL) groups. There were no statistically significant differences between the two groups in terms of age, gender distribution, BMI, stone size, or preoperative hemoglobin levels (p > 0.05 for all parameters), indicating comparability at baseline (Table 1).

Table 1. Baseline Demographic and Clinical Characteristics of Study Participants

Figure 1. Comparision of Baseline Characteristics between S-PCNL and M-PCNL

Perioperative Blood Loss

The primary outcome of perioperative blood loss showed a statistically significant difference between the two groups. The mean postoperative drop in hemoglobin was significantly greater in the S-PCNL group (2.1 ± 0.6 g/dL) compared to the M-PCNL group (1.2 ± 0.5 g/dL), with p < 0.001. Similarly, estimated intraoperative blood loss was notably higher in the S-PCNL group (189.5 ± 41.3 mL) than in the M-PCNL group (112.8 ± 36.7 mL), also reaching statistical significance (p < 0.001). These findings are presented in Table 2.

Table 2. Comparison of Perioperative Blood Loss Between S-PCNL and M-PCNL Groups

Figure 2. Comparison of Perioperative Blood Loss Between S-PCNL and M-PCNL Groups

Operative Time and Postoperative Outcomes

The mean operative duration was slightly longer in the M-PCNL group (78.6 ± 12.3 minutes) than in the S-PCNL group (72.4 ± 10.7 minutes), and this difference was statistically significant (p = 0.028). Despite the longer operative time, the M-PCNL group demonstrated a more favorable profile regarding perioperative blood parameters.

Minor complications such as transient hematuria or febrile episodes were observed in 6 (12%) patients in the S-PCNL group and 4 (8%) in the M-PCNL group; this difference was not statistically significant (p = 0.51). No major complications or perioperative mortality were reported in either group (Table 3).

Table 3. Operative Time and Postoperative Complications

Figure 3.Comparision of Operative Time  Between S-PCNL and M-PCNL

This prospective observational study compared perioperative blood loss and surgical outcomes between Standard PCNL (S-PCNL) and Mini-PCNL (M-PCNL) in patients undergoing renal stone surgery. The results demonstrate that Mini-PCNL is associated with a significantly lower drop in hemoglobin, reduced estimated intraoperative blood loss, and decreased transfusion requirements. These findings underscore the clinical advantages of utilizing miniaturized access tracts to mitigate renal trauma and hemorrhagic complications.

The mean hemoglobin drop observed in the S-PCNL group (2.1 ± 0.6 g/dL) was significantly higher than in the M-PCNL group (1.2 ± 0.5 g/dL), corroborating earlier studies which suggest that smaller tract size contributes to less vascular disruption and parenchymal injury [6, 11]. Similarly, our study reported a higher mean estimated blood loss in the S-PCNL group (189.5 ± 41.3 mL) versus M-PCNL (112.8 ± 36.7 mL), a trend that is consistent with existing evidence emphasizing Mini-PCNL’s hemostatic superiority [7, 12].

Our transfusion rates (16% in S-PCNL vs. 4% in M-PCNL) are in line with those reported in meta-analyses and randomized trials, highlighting tract size as a predictive factor for intraoperative bleeding and the need for transfusion [7, 10]. These observations have substantial clinical relevance, especially in pediatric patients or individuals with underlying coagulopathy, where blood conservation is paramount [6].

Operative time was marginally longer in the M-PCNL group (78.6 ± 12.3 min) than in the S-PCNL group (72.4 ± 10.7 min; p = 0.028), likely attributable to technical challenges in fragmenting and retrieving stones through narrower tracts. Previous studies have similarly reported slightly increased operative times with Mini-PCNL due to limited visual fields and constrained instrumentation, although these do not generally translate into increased complications or morbidity [9, 11].

Importantly, the complication rates in our study did not differ significantly between groups. Minor complications were observed in 12% of S-PCNL and 8% of M-PCNL cases, with no reports of major complications or mortality in either cohort. These results reaffirm the safety profile of Mini-PCNL, a finding echoed in comparative trials and systematic reviews [8, 11, 12].

Beyond the scope of intraoperative bleeding, Mini-PCNL has been associated with reduced postoperative pain, lower analgesic requirement, shorter hospitalization, and faster return to routine activity—advantages that have been well-documented but not evaluated in our current study [6, 9]. Nonetheless, limitations exist. Mini-PCNL may be less effective for managing large staghorn calculi or when rapid stone clearance is essential, due to challenges in accessing calyceal extensions and retrieving larger fragments [11].

The present study is strengthened by its prospective design and balanced group allocation. However, it is limited by its single-center nature and modest sample size, which may restrict the detection of less common complications. Additionally, while we evaluated blood loss and transfusion needs, we did not assess stone-free rates, pain scores, or hospital stay duration—important endpoints in the comprehensive assessment of surgical efficacy [8, 12].

Future multicenter studies with larger cohorts and longer follow-up are needed to further validate the advantages of Mini-PCNL, especially in special populations such as children, patients with solitary kidneys, or those with complex stones [6, 10].

This study highlights that Mini-PCNL is a safer and less invasive alternative to Standard PCNL in terms of perioperative blood loss, demonstrating significantly lower hemoglobin drop, reduced estimated blood loss, and decreased transfusion requirements. While the Mini-PCNL group showed a slightly longer operative time, there were no significant differences in complication rates or postoperative morbidity. These findings suggest that reducing tract size can effectively minimize renal trauma without compromising surgical safety. Mini-PCNL should be considered a preferred option, particularly in patients with high bleeding risk or those requiring nephron-sparing strategies. Further large-scale studies are recommended to validate long-term outcomes and stone clearance efficacy.

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