Comparison of stone clearance rate based on upper, middle, or lower calyx puncture in Mini Percutaneous Nephrolithotomy (mPCNL)

morbidity, particularly in the chest. Lower calyx punctures have less intraoperative and postoperative morbidity, but their stone removal rates are lower than those of other procedures. Therefore, the balance between stone clearance rate and morbidity has been achieved using middle calyx puncture.


Introduction
Urolithiasis is one of the most common diseases.More than 70% of the patients in urology clinic are of urolithiasis. 1 Management of urolithiasis depends on the size, site, and consistency of the stone as well as evolving technology and expertise available.There are multiple options available for the management of renal stones, such as open surgery, endourology, laparoscopic surgery, etc. Percutaneous Nephrolithotomy (PCNL) is the most common surgical technique used for the management of renal stones, particularly for those with more than 2 cm stones. 2 hematuria to intestinal perforation, various innovations in technique and equipment have been made. 3We do miniPCNL with 12Fr Nephroscope.Puncture of the kidney is one of the most important steps in PCNL.We puncture the upper, middle, or lower calyx of the kidney depending on the location of the stone.
Upper calyx puncture is extremely useful for the clearance of stone in the upper calyx, pelvis, and even lower calyx but it is associated with thoracic complications. 4,5Middle calyx is less commonly used but provides the shortest track to the pelvis and can give access to the upper and lower calyx in favorable anatomy. 6Lower calyx puncture is exclusively used for lower calyx stone but sometimes it is associated with colon perforation. 7veral studies compare the upper, middle, or lower calyx puncture, but very few compare all three calyces at once.In this study, we compared the miniPCNL's stone clearance rate based on access to the upper, middle, or lower kidney calyx.

Methods
This single center prospective non-randomized study was performed in department of urology, KIST medical college.
were included in study.Patients were recruited either from emergency or from outpatient department.Diagnosis was done by history, examination, ultrasonography of the abdomen and pelvis and CT Urogram.Perioperative management was done according to standard protocol.Permission was taken from the institutional review board.The study period was from September 1, 2021 to November 16, 2022.
A sample size of 87 was achieved with the website http:// www.raosoft.com/samplesize.html.The margin of error is 6%.The statistical analysis was carried out using Statistical Package for the Social Sciences for Windows software, were used to analyze the data with the mean, the range for medians and the variance reported for continuous variables, and the proportions reported for categorical variables.
Pearson's chi-square and Fisher's exact test were used for comparisons of percentages.Then the patient was changed to the prone position.The puncture was done with an 18fr diamond tip needle.The decision to puncture the upper, middle or lower was taken after a retrograde pyelogram.The straight tract which was in the line of maximum bulk of stone was chosen as the best access.Tracts were dilated to 18Fr with the help of an alken dilator.12Fr mini-nephroscope was used.Lithotripsy was done by pneumatic lithotripter.Renal drainage was done with a DJ stent and /or nephrostomy tube according to the surgeon's decision.Postoperatively nephrostomy tube was removed on day 1 and foley catheter was removed on day 2 and the patient was discharged as early as practicable.X-ray in sonography. 8

Parameters
Stone-free status was considered as the primary outcome and complications of PCNL (intraoperative, immediate postoperative, and late complications) was taken as a secondary outcome.

Results
100 patients were included in this study.59 were male and 41 were female.In 23% of patients upper pole puncture was done, in 33% of patients middle pole puncture was done and in 44% of patients lower pole puncture was done.
and clinical characteristics (

Discussion
Numerous changes have been made to the PCNL 9 The PCNL track's commonly used in the management of large-size stones it is have been tried. 10 the infundibulum and calyces choice of puncture site has been key to the success of the procedure.11 The basic principle has been to choose the tract which will provide access to the maximum bulk of the stone.12 In this study, we found stone clearance rate was 91.3% in the upper calyx, 75% in the lower calyx, and 87.8% in the middle calyx.A maximum stone-free rate has been found in the upper calyx.The reason for this may be the know kidney is oriented ventro-laterally and more inclined towards the midline. 13If the PCNL track is from the upper calyx and it is more medial so we can have easy access to the upper calyx, pelvis, and lower calyx.It also prevents the migration of stone to another calyx because of the direction 14 Anatomy of the upper calyx makes the puncture relatively easy.15 Arrangement of calyces is such that there is no anterior and posterior calyx.16 So we have to choose medical vs lateral calyx. Moproximity of the calyx toward the ventral side drawbacks to this technique.Most of the time, site of the upper pole puncture is above the 12th rib and sometimes it is even above the 10th rib.16 As the site of puncture is higher it is associated with multiple complications such as the liver and spleen, and sometimes even trauma to the lung parenchyma.17 That is why it is not advisable to choose the puncture site above the 10th rib.During the procedure ergonomically it is comfortable for the right-handed person to procedure in the left kidney and vice versa.17 The middle calyx is chosen if the maximum bulk of the stone lies in the direction of the middle calyx or if the stone is in the renal pelvis or lower calyx and or pelvis.For the miniPCNL tract middle calyx seems to be a versatile track.Most of the time we were able to reach the stone from the top thus preventing the migration of stone to the upper calyx.Except in a few unfavorable pelvicalyceal systems, the mini nephroscope could reach the upper and lower advantage of middle calyx puncture is that because of a favorable angle, the guidewire can reach the ureter most of the time making tract dilatation easy and reducing the chances of tract loss.As we see the distinct anterior and posterior division of the middle calyx so it is very important to enter the pelvicalyceal system from the posterior calyx.In the middle calyx puncture, very often puncture site is supracoastal but the calyx is entered from the lateral part of the ribs.So the chances of pleural violation are limited.10 Lower calyx access is considered the safest among all three calyces.18 It is chosen if the bulk of the stone is in its direction.The compound calyx axis of the orientation the posterior calyx for the entry to the pelvis. Soetimes if the location of the stone is in the anterior calyx then pelvis.Another disadvantage of lower calyx access is the migration of the stone to the upper calyx.In this scenario, if the nephroscope cannot be negotiated into the upper calyx another track in the upper calyx.In this study, we have found the maximum complication in upper calyx puncture.The reasons for this are during upper calyx puncture the tract goes between the ribs through the diaphragm and sometimes through the parietal pleura.
pain will also compromise the expansion of basal areas of the lung leading to atelectasis and pneumonia.As mentioned associated with intraoperative postoperative bleeding.Even in the supracoastal puncture entry site of the calyx is observed by Soares et al and El-Nahas that this makes the tract more oblique and longer subsequently causing bleeding during manipulation. 4,18d lower calyx punctures [P=0.02,P=0.98, P=0.03].
Although 48.48% [16] of the puncture were supracoastal calyx.This is because all the supracoastal punctures were at the lateral surface of the 11th Intracoastal space.
The stone clearance rate was maximum in the upper calyx.
another calyx, we can have better endoscopic clearance of the stone.The stone clearance rate is lowest in the lower calyx because of the migration of stone fragments.In lower calyx access need for another track if there is a stone that cannot be reached from the current track or the stone migrate to another track.
The upper pole of each kidney lies anterior to the posterior portion of the 11th and 12th ribs and during exhalation the lower limit of the parietal pleura crosses these ribs obliquely, such that the lateral portions of these ribs are inferior and lateral to the lower limit of the pleura. 20The incidence of thoracic complications during supracostal punctures in various studies ranges between 3% and 16%. 20,21is study has some limitations.As a non-randomized study, it is important to acknowledge that there may be some inherent bias in the sample selection process.The anatomy The stone clearance rate is also determined by favorable anatomy.Another bias is during the choice of which calyx to puncture.There are no clear-cut criteria to choose the site of puncture.It is only a subjective judgment.

Conclusion
An upper calyceal puncture can produce the highest stone postoperative morbidity, particularly in the chest.Lower calyx punctures have less intraoperative and postoperative morbidity, but their stone removal rates are lower than those of other procedures.Therefore, the balance between stone clearance rate and morbidity has been achieved using middle calyx puncture.

Table 1 . Baseline characteristics 66
A All the procedures were done under general anesthesia.6Fr ureteric catheter was inserted in the lithotomy position.

Table 1
).Average age of the patient was 33.35 years (Range 18-65 years).The mean stone burden of the patients was 380.680 mm2.The average 1504].The average time for surgery was 75 min [range 42 min to 102min].The average time for surgery according to access was 67.34 min for the upper calyx, 63.12min for the mid-calyx, and 64.07 min for the lower calyx.Table2demonstrates details of intraoperative and postoperative events.Thirty-seven patients had supra-coastal entry points of the needle and the rest 63 had infra-coastal entry points.While breaking the stone with a pneumatic lithotripter 5 patients had renal pelvis perforation which was managed with DJ stenting.Urine leak from the nephrostomy tube was observed in 5 patients after removal of the tube but no such complication was seen in tubeless PCNL.

Table 3 .
Complications were recorded as grade I, II, and