Millions of people worldwide suffer with renal calculi, also referred to as kidney stones, a common urological ailment [1]. Kidney stones have plagued humanity for generations, beginning about 4000 BC. It is a growing urological condition that affects 12% of people worldwide. Kidney stones afflict 1–15% of persons worldwide at some point in their lives [2]. Furthermore, up to 50% of renal stones may reoccur [3]. Globally, kidney stone incidence is rising at all ages, which is causing more adults and children to need treatment for kidney stones [4]. Recent technological advancements, particularly the development of minimally invasive procedures like extracorporeal shock wave lithotripsy (ESWL), percutaneous nephrolithotomy (PCNL), and retrograde intra renal surgery (RIRS), have had a significant impact on kidney stone care [5]. Since PCNL and retrograde intrarenal surgery (RIRS) are linked to higher clearance rates, there has been a consistent decrease in the use of ESWL for renal calculi that are 1-2 cm in size, and by an increase in their use. A high stone-free rate and a shorter total treatment duration are attained by the efficient PCNL approach [6]. One of PCNL's main disadvantages is its comparatively increased morbidity, which includes trauma and hemorrhage. Mini PCNL and other minimally invasive percutaneous techniques (Minimally-invasive PCNL) were developed in order to reduce these consequences by reducing the size of the tract [7]. To lower the procedure's morbidity, mini-PCNL substitutes a 12-14F nephroscope with a 15-18F Amplatz sheath for the usual PCNL's 24-30F sheath [8]. Mini-PCNL uses the tract of less than 20 Fr with comparable stone-free rates and lower morbidity than normal PCNL [9]. Since then, mini-PCNL has expanded globally and gained popularity as a kidney stone therapy method with low morbidity and good results. Another minimally invasive technique for treating upper tract urinary calculi is RIRS, also known as flexible ureterorenoscopy [10]. RIRS has been viewed as a viable substitute for percutaneous techniques due to its attributes of little damage, quicker recovery, ease of operation, and fewer contraindications. While small PCNL does not necessarily require a laser machine, RIRS has investment issues because it requires both a fragile scope and a laser machine, which is undoubtedly more expensive than a standard nephroscope. Renal stones can be effectively treated with mini PCNL and RIRS. Mini-PCNL and RIRS have limits despite their many advantages. Both methods necessitate specific knowledge and training, which could result in lengthier procedure times and more learning curves for urologists [11]. Furthermore, the expense of purchasing and maintaining specialised equipment may provide financial difficulties for healthcare organizations, preventing some patients from accessing these cutting-edge treatments [12].

Aim and Objectives:

1. To assess the stone clearance rate of Mini-PCNL and RIRS in renal calculi smaller than 2 cm.

To evaluate the effectiveness, cost-effectiveness, and complications following surgery of the two methods.

This prospective comparative study was done at Department of General Surgery of Pacific Medical College & Hospital, Udaipur (Rajasthan) from November 2022 to May 2024 (18 months duration).

Inclusion Criteria:

• All patients with diagnosis of nephrolithiasis of size less than 2cms
• Patients who provided written informed consent for the study

Exclusion Criteria:

• Patients with diagnosis of nephrolithiasis of size larger than 2cms.
• Patients diagnosed with staghorn calculi
• Patients who do not agree to give consent to participate in the study.

A total of 50 consecutive patients of renal stones were included in the study after informed consent. The patients were randomly allocated to undergo either a Mini PCNL or RIRS group.

Group A: Mini PCNL (25 patients)

Group B: RIRS (25 patients)

In all patients, a detailed history was taken and physical examination was done. Laboratory investigations were carried out as per requirement. These included haemogram, renal function tests, blood sugar level, coagulation profiles and urinalysis with urine culture and sensitivity.

Radiological evaluation was done in the form of plain X-ray of kidney, ureter and bladder (KUB) and ultrasound of the abdomen. All patients underwent an intravenous urography (IVU) or CT Intra Venous Urography (CT IVU) whatever was feasible, prior to the procedure to assess the anatomy and functioning of kidney.

Patients underwent surgeries according to standard hospital protocols. Safety and efficacy of both the procedures along with other post-operative complications were comparatively evaluated in both groups. The operation time was defined as the time from the start of the first procedure to the termination of the surgical operation. For PCNL and RIRS, it was started with the puncture for an access tract and placement of flexible ureteroscope, respectively. The duration of hospitalization was defined as the time from the day of surgery to discharge for each session. Stone-free status was assessed by ultrasonography and/or a KUB, and was defined as the absence of any stones.

Statistical analysis: To analyze the data acquired, Statistical Package of Social Services (SPSS) version 20 was used. The quantitative data was presented in the form of the mean, median, standard deviation, and confidence intervals. The information was presented using qualitative statistics such as frequency and percentage. The student's t test (T) is used to dealing with quantitative independent variables. Pearson Chi-Square was used to assess qualitatively independent data. The significance of a P value of 0.05 or less was determined.

A total of 50 patients fulfilled the inclusion criteria were enrolled and evaluated. The mean age, with Mini PCNL was 36.56 years and RIRS patients were 43.40 years. However, this difference is not statistically significant.

The mean stone size, mean duration of surgery, Pre operative and Post operative hemoglobin levels for patients undergoing Mini PCNL and patients undergoing RIRS were not statistically significant (P>0.05).

Significantly low hematocrit level was found in RIRS group compared to Mini PCNL group (P<0.05).

The mean hospital stay was significantly longer in Mini PCNL patients as compared to RIRS patients (P<0.05), highlighting a notable disparity in recovery times between the two procedures.

The Visual Analog Scale (VAS) score was higher for Mini PCNL patients, compared to RIRS patients (P<0.05), indicating that patients undergoing Mini PCNL experienced more postoperative pain than those undergoing RIRS.

Table 1: Mean comparison of among both the groups

The location of stones varied, with the impacted at PUJ (44% in Mini PCNL and 20% in RIRS) and pelvis (28% in Mini PCNL and 36% in RIRS) being the most common location for both groups. No statistical significant difference in the distribution of stone locations between the two groups (P>0.05).

Graph 1: Location of stone among both the groups

Fever and sepsis were more frequent postoperative complications in the RIRS group (both 20%) compared to the Mini PCNL group (8% for both). The results of postoperative complications were statistically not significant difference between both the groups (P>0.05).

Table 2: Postoperative Complications among both the groups

Additional analgesic use was required by 12% of Mini PCNL patients, while none of the RIRS patients required them. Secondary interventions needed only in the RIRS group (8%), with none required in the Mini PCNL group, these difference was not statistically significant (P>0.05)

There was a significant difference in the need for prior DJ stenting, none required in the Mini PCNL group compared to 32% in the RIRS group (P<0.01).

Table 17: Need for Secondary Intervention among both the groups

The presence of residual stones was higher in the RIRS group (16%) compared to the Mini PCNL group (4%). The stone clearance rate was higher in the Mini PCNL 96%) compared to the RIRS group (84%). However, this difference did not reach statistical significance (P>0.05).

Graph 2: Comparison of Residual Stones among both the groups

Patients presenting with flank pain were the majority in both groups, with 44% in Mini PCNL and 68% in RIRS. The distribution of presenting complaints showed no significant differences between the two groups (P>0.05), indicating similar symptom profiles for both procedures.

Graph 3: History of Presenting Complaints among both the groups

The management of small renal calculi has evolved in the last decade with the advent of newer procedures, such as Mini PCNL and RIRS. The past few years has seen significant advancement in endoscopic instrumentation and laser technology and faster and minimally invasive treatment for stone disease. On the other hand, because of patients growing reluctance for repeated hospitalization and treatment with ESWL, where stone clearance rates are as low, Physicians are questioning the use of conservative noninvasive treatments.

In our study, majority of the patients undergoing Mini PCNL and RIRS were younger age group (31-40 years) and male predominance, but no statistically significant difference was found between the groups in terms of age and gender. Our results were similar with the Kumar V, et al [13] and Zhang J, et al [14].

In the present study, majority of the patients presented with flank pain in both the groups. There was no significant difference among the distribution of presenting complaints between the two groups, in agreement with the Ruhayel et al [15].

The mean stone size for patients undergoing Mini PCNL and RIRS were comparable between the two groups (p>0.05) in the current research, this observation is consistent with Sebaey, et al [16] and Guven S, et al [17]. These findings highlight that both Mini PCNL and RIRS are applied to patients with similar stone burdens.

We have found that the stone impacted at PUJ and pelvis being the most common location for both groups, no significant difference among stone locations between the two groups, in accordance with the Park et al [18].

Placement of DJ stents in Mini PCNL procedure was significantly higher as compared to RIRS procedure, this mirrors results from studies by Zhang et al[14] and Xiao et al [19], highlighting the procedural necessity for DJ stents in Mini PCNL to ensure postoperative drainage and prevent complications.

There was no statistically significant difference in mean duration of surgery, pre and post operative hemoglobin levels among patients undergoing Mini PCNL and RIRS in this study, our findings consistent with the Kanchi, et al [20] and Soderberg, et al [21].

In our study, the stone clearance rate was higher in the Mini PCNL compared to the RIRS group (P>0.05). This finding concurs with studies by Meyyappan K, et al [22] and Kuo et al [23], suggesting that while RIRS might have a slightly higher rate of residual stones, the difference is not significant enough to influence procedural choice solely based on this criterion.

We have reported that the mean hospital stay was significantly longer in Mini PCNL as compared to RIRS patients; this finding is supported by Shah et al [24], which also reported longer hospital stays for Mini PCNL, emphasizing the quicker recovery associated with RIRS.

The VAS score was significantly higher for Mini PCNL patients compared to RIRS patients, indicating that patients undergoing Mini PCNL experienced more postoperative pain than those undergoing RIRS, in accordance with the El-Nahas et al [25]. This was likely due to the more invasive nature of Mini PCNL.

Current study found that the postoperative complications was higher in the RIRS group as compared to the Mini PCNL group, but the difference was not significant statistically (p>0.05). This matches findings by Somani et al [26] and Jain, et al [27].

In our study additional analgesic was required only in Mini PCNL patients, while none of the RIRS patients required them, while secondary interventions were needed only in the RIRS group, with none required in the Mini PCNL group, but this difference was not statistically significant (P>0.05). This finding is supported by Krambeck et al [28].

We have concluded that the Mini PCNL has higher stone clearance rate, significantly longer hospital stays and higher postoperative pain levels for patients, while RIRS patients showed a higher post operative complication. DJ stent placement was significantly more common in Mini PCNL, whereas prior DJ stenting was more prevalent in RIRS patients. These findings suggest that while both procedures are effective for treating kidney stones, they have distinct postoperative recovery profiles and procedural characteristics.

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