The prevalence of nephrolithiasis is reported to be 13% [1].In addition, there is also a noticeable increase in the number of patients who receive an active treatment for upper urinary tract calculi (UUTC), Parketal., (2016) reported an increase of different modalities of intervention including ESWL, ureteroscopy (URS) and percutaneous nephrolithotomy (PNL) by 102, 110, and 180%, respectively, over the last 10 years [2]. Although many factors are expected to influence the treatment decision for patients with upper tract, painrelief remains the first concern nana cute episode [3]. Non-steroidalanti-inflammatory drugs (NSAID) are the first-line drugs with a better efficacy in pain control compared to opioidsonlyor combinedopioidsand antispasmodics[4].Pethidineinparticularshouldbeavoidedbecauseofthehigherrateofvomitingand need for further analgesia [5]. Traditionally, after control of pain, the definitive treatment of stones was delayed with options including medical expulsive therapy (MET), SWL, and ureteroscopy [6].Recently, the utilization of both SWL and URS as emergen cyprocedures with the aim to decrease the time of stone-related symptoms, morbidity, and possible complications was found to be safe and effective[7].

This study was conducted in a single tertiary care urology hospital between February 2023 to August 2024. After obtaining institutional ethical committee clearance, 190 patients with mid and distal ureteric calculus were enrolled in this study. Mid ureteric calculus (overlying the sacroiliac joints), lower ureteric calculus (below the lower border of the sacroiliac joint to vesicoureteric junction) of size <15 mm was treated with supinepositioned with trans-abdominal approach using pronated shock head ESWL. The primary objective was to evaluate the efficacy and safety of extracorporeal shock wave lithotripsy using supine positioned with trans-abdominal approach using pronated shock head ESWL for mid and distal ureteric in the parameters like mean age of presentation sex ratio, laterality, stone location, mean size, mean Hu, mean fluoroscopic time, mean treatment time, mean no shock wave given, time to stone free, stone free rate, mean sessions number and post procedure complications. Any patients having Previous history of ipsilateral renal surgery, Positive urine culture, Uncorrected Coagulopathies, Morbidobesity, Radiolucent stone, bilateral renal and ureteric stone, renal insufficiency, bonyde formities, pregnancy, solitary kidney, Unwilling patients were excluded from the study. All patients were evaluated with ultrasonography KUB (Kidney-Ureter-Bladder), X-ray KUB (for radio opacity), NCCT (Non-Contrast Computed Tomography) KUB, urine culture/sensitivity test, renal function test and coagulation profile.

In this study we enrolled total 190 numbers of patients initially with mid and lower ureteric calculus in which 20 patients with mid ureteric calculus and 170 patients with lower ureteric calculus. It is found to beneficial in lower ureteric calculus. In mid ureteric calculus ten patients experienced severe pain hence further procedure was abandoned. We didn’t localize the calculus on fluoroscopy in four patients. Finally, we offered ESWL in 6 patients with mid ureteric calculus in which stone clearance achieved in 2 patients and rest four patients send for surgical intervention with residual stones after first session. For lower ureteric calculus four patients did not come for follow up after the first session, two patients didn’t agree for further ESWL session with residual stones after first session, and one patient had nausea and vomiting along with severe pain so referred for surgical intervention. Hence seven patients were excluded from the study analysis. Finally, total no of 163 patients analyzed in the study (51 females and 112 males); all important features enlisted in table1. Overall SFR (stone free rate) was 85.88% (140/163). Stone cleared after first session 80% (112/140) cleared after one session and 20% (28/140) underwent more than one session. Twenty-three patients (14.2%) stone were not fragmented even after three sessions of ESWL. The causes of failure were either lack of disintegration or failure of clearance. All failure cases were referred for surgical intervention. Stone length, width, stone HU had a significant effect on SFR. (Table1). Patients are classified on the basis of stone dimensions and HU. (Table 3). The mean stone length was 7.79 and 11.2mm in stone Free and stone not free group respectively. For stone length<10mm, SFR was 97.8% (136/139) compared to 16.66% (4/24) for stone length of >=10mm (p <0.00001). The mean stone width was 7.43 and 10.56mm in stone free and stone not free group respectively. For stone width<10 mm, SFR was 96.45% (136/141) compared to 18.18%(4/22) for stone width of >=10 mm(p <0.00001). The mean stone attenuation in stone free group was638.22 and 978.76 HU in stone not free group. For stone attenuation⩽900 HU, SFR was 97.87% (138/141) compared to 9.09% (2/22) for stone attenuation >900 HU (p <0.00001). Mean BMI (Body Mass Index) in these patients was 26.58 kg/m2. No patient experienced cardio-respiratory distress in supine position. Most patients experienced transient high color urine relieved after taking medication. Two patients had urinary tract infection post ESWL in spite of having a prior sterile urine culture. They were managed with iv antibiotics and conservative line of management. Two patients had episode of ureteric colic with nausea, both of them needed inpatient treatment. None of these four patients needed endoscopic intervention. No patient experienced any bowel and bladder complication. Table 1. Features of distal ureteric calculus Variables range/number range/number SD Age(years) (18-76) 46.19/45 13.86 Length (mm) (6-15) 8.28/8 1.76 Width (mm) (5-12) 7.87/8 1.66 HU (300-1500) 701.04/658 234.322 BMI(kg/m2) (18-40) 26.58/26 4.67 Symptoms duration(days) (6-72) 35.65/35 14.16 Treatment time (minute) (27-55) 37.98/38 5.66 Fluoroscopic time(minute) (1-6) 2.37/2.20 1.04 No. of shockwave (1800-3500) 2543.74/2400 561.00 Time to achieve(days) (12-40) 26.56/26 7.99 stone free status Table 2. Factors affecting stone free rate. Variable Mean value Stone free/not free p-Value Age 46.27 vs 45.69 0.852 Stone length (mm) 7.79vs 11.2 0.00001 Stone width (mm) 7.43vs 10.56 0.00001 BMI (kg/m2) 26.23 vs 28.70 0.055 Stone attenuation (HU) 638.22 vs 978.76 0.00001 Fluoroscopic time (min) 2.31vs 2.80 0.08 Treatment time (min) 37.7 vs 39.73 0.143 Symptom duration (days) 35.43 vs 37.00 0.643 Table 3. Stone characteristics and stone free rate. Variables Group No. of patients Stone free Stone not free Stone free rate p-Value Stone A (<10mm) 139 136 3 97.8 length B (>=10mm) 24 4 20 16.66 0.0001 Stone A (<10mm) 141 136 5 96.45 width B(>=10mm) 22 4 18 18.18 0.0001 Stone A (⩽900 HU) 141 138 3 97.87 Attenuation B (>900 HU) 22 2 20 9.09 0.0001

There are different treatment options for ureteric stones consist of Conservative line of management where spontaneous passage of stones occurs with the help of MET therapies, URSL and retroperitoneoscopic or open uretero-lithotomy. Spontaneous passage of distal ureteric stone mainly depends on different factors like the dimensions of stone, degree of obstruction, symptom severity, observation time etc [7] The spontaneous passage rate for stones 1 mm in diameter was 87%; for stones 2–4 mm, 76%; for stones 5–7 mm, 60%; for stones 7–9 mm, 48% and for stones larger than 9 mm, 25%. Spontaneous passage rate as a function of stone location was 48% for stones in the proximal ureter, 60% for mid ureteral stones, 75% for distal stones and 79% for ureterovesical junction stones. [7,8,9] Chaussy et al., conducted study in 1980 for the treatment of urinary stones and became the treatment modality of choice for uncomplicated renal and ureteral stones <20 mm in diameter due to its safe and non-invasive nature [10,11,12]. There are several factors have been studied to affect ESWL outcome. These classified into patient related-factors such as age, gender, BMI, anatomy of urinary tract, and stone related factors obtained from imaging studies such as stone size, location, density, Skin-to-Stone Distance (SSD), and the type and properties of the used lithotripter. It was initially used to renal and proximal ureteral stones, and then rapidly used to stones at middle and distal ureter. The success rate of ESWL for urinary stones was significantly increased along with the improvement of techniques, recommendation of ESWL for the treatment of distal ureteral stones was not established. [13] The effectiveness of ESWL can be improved by using different positions during the treatment of distal ureteral stones were attempted, [14] from which the prone and supine positions were most frequently adopted. Though it had been proved that prone position was a safe and effective choice, limitations of this position existed.[15] On the other hand, because shock waves might be blocked by bony pelvis, more energy was needed to obtain satisfactory effectiveness by traditional supine approach.[16] Jenkins et al. [17] conducted a study using SWL in a prone position to fragment distal ureteral calculi. However, there are drawbacks in performing SWL in the prone position, including patient discomfort on inspiration and expiration, increased intra-abdominal pressure, and decreased lung capacity [17,18]. With advances in technology and increase in confidence and experience, more urologists regard SWL in a supine position to be more cost effective. They have claimed that the SWL shockwaves can traverse gaps in the bony pelvis, such as the sciaticum majus foramen and sciaticum minus foramen, to reach and fragment stones blocking the distal ureter [17]. Becht et al [19] reported the new position enabling x-rays and shock waves to enter through foramen obturator or greater sciatic notch, the trans gluteal supine approach was gradually applied in low ureteral stones. SFR was 95 % in this study. Phipps et al [ 20] compared the outcomes of extracorporeal shockwave lithotripsy (ESWL) for distal ureteric stones treated using the prone and trans gluteal (supine) approaches in a tertiary referral stone unit using a fourth-generation lithotripter. Trans gluteal ESWL to stones within the distal ureter leads to significantly higher stone-free rates than treatment using the prone approach (p<0.001). The overall success rates for treatment within the prone and trans gluteal groups were 63 and 92%, respectively (<0.001).Acker-et-al[ 21] used horse riding position for treating distal ureteric calculus. SFR was 89.4 in this study In the present series, for distal ureteric calculus the overall SFR was 85.88%; this success rate is within the reported range (73–86%)[22] higher than sarkar et al (83.57%)]. In the present study we used dornier delta compact-2 second generation using complete supine positioned transabdominal approach with pronated shock head as previously done by sarkar et al study. In the present study we enrolled patient presented with mid and distal ureteric calculus but we didn’t get satisfactory result in mid ureteric calculus may be due to presence of bowel gas and increased skin to stone distance, bony iliac-sacral crest, so shockwave reaching the stone with attenuation of only 20% of its power [23] and in some cases this procedure could not be feasible. In the present study, the simple supine position of patient provided a great comfortable treatment option for patient compared to prone position. The specific prone position of ESWL shock wave head coming from above on to the anterior abdominal wall allowed for better visualization and easy localization of stone (Figures 2 and 3). Compared to the earlier more difficult ‘modified supine’ positions of sitting or straddle positions, with this relaxed supine position we could achieve SFR of 85.88. Only 17.17% required more than one session for clearance of stone. This SFR is at par with other supine SWL studies [24]. Abdel-Khalek et al.[25] found BMI as a significant prognostic factor for SFR in prone position ESWL. Although in our study the mean BMI does not have significant association with stone free rate versus stone not free in stone not free group was slightly higher than in patients who did achieve stone free status (26.23 vs 28.70 kg/m2 , p value-0.055). We hypothesize that this difference can be because of better positioning and localization of stone in supine position compared to prone position ESWL in previous study. So, we can recommend this approach in all distal ureteric calculi patients planned for ESWL, more so in patients with cardiac compromise or respiratory issues. Patients developed minor complications like transient hematuria, small erythematous areas, or varying degrees of petechiae and resolved spontaneously. Limitations: Patients were assessed with x ray KUB images after session of ESWL, usually less sensitive for detecting residual fragments. We did not get satisfactory outcome in mid ureteric calculus may be due to presence bowel bowel gas, bony iliac-sacral brim increased stone to skin distance, difficulty in localization of calculus. Hence more study required for mid ureteric calculus in details at the multicenter level. The study was conducted at a single center with small sample size which might not be representative to the whole population, the large multi-center study or metanalysis is planned to validate this result in different cohort.

ESWL using supine transabdominal pronated shock head is very effective, non-invasive, safe, feasible and comfortable to treat distal ureteric calculus in patients with acute presentation, it is highly effective in stone size <10mm and hu<900 ureteric stone.it can be considered in patients with cardio-respiratory discomfort while we didn’t get satisfactory result in mid ureteric calculus.

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