Safety and Efficacy of the Mid-Calyx Access Versus the Lower-Calyx Access in Paediatric Percutaneous Nephrolithotomy (PCNL)

By Asif Khan¹, Akhtar Nawaz², Riaz Ahmad Khan¹, Nizam Uddin², Sami Ur Rahman³, Kaleemullah Jan⁴

Affiliations

1. Department of Paediatric Urology, Institute of Kidney Disease, Peshawar, Pakistan
2. Department of Urology, Saidu Group of Teaching Hospital, Swat, Pakistan
3. Department of Urology, Miangul Abdul Haq Kidney Hospital, Swat, Pakistan
4. Department of Urology, Swat Medical Complex, Teaching Hospital, Swat, Pakistan

doi: 10.29271/jcpsp.2025.08.1014

ABSTRACT
Objective: To compare the safety and efficacy of the mid-calyx access (MCA) and the lower-calyx access (LCA) in paediatric percutaneous nephrolithotomy (PCNL).
Study Design: Descriptive study.
Place and Duration of the Study: Department of Paediatric Urology, Institute of Kidney Disease, Peshawar, Pakistan, from January 2022 to October 2024.
Methodology: Two hundred paediatric patients divided into two groups (85 MCA and 115 LCA) were retrospectively analysed. Demographic data, stone clearance rates, operative times, blood loss, postoperative complications, and hospital stays were compared. Statistical analysis was performed using the independent t-test and the Chi-square test, with significance set at p <0.05.
Results: The mean age was similar between two groups (8.38 ± 3.94 vs. 8.42 ± 3.75 years, p = 0.94), and gender distribution was comparable (lower calyx: 53 females and 62 males; mid-calyx: 40 females and 45 males; p = 0.89). Stone clearance rates were also non-significant (MCA 90.59%, LCA 84.35%; p = 0.19). MCA had significantly shorter operative time (43.0 [41.0, 46.0] minutes compared to 54.0 [50.0, 57.5] minutes; p <0.001) and fewer urinary tract infections (10.59% compared to 21.74%; p = 0.03). Hospital stays were shorter for MCA (1.49 ± 0.22 days compared to 1.91 ± 0.77 days; p <0.001). Other complications, including bleeding, renal injury, and postoperative fever were rare and not significantly different between groups.
Conclusion: Both MCA and LCA are safe and effective for paediatric PCNL. MCA offers more advantages, including shorter operative time, reduced urinary infections, and faster recovery, making it a preferable option in selected cases.

Key Words: Mid-calyx approach, Lower calyx approach, Percutaneous nephrolithotomy, Safety, Efficacy.

INTRODUCTION

Nephrolithiasis is becoming increasingly prevalent in paediatric urology throughout the world.¹ The prevalence of nephrolithiasis varies across regions, with studies reporting rates of 1-5% in Asia.^2,3 Nephrolithiasis occurs when is an excessive formation of crystals within the urinary system or insufficient elimination of crystals through urine production. Metabolic abnormalities such as hypercalciuria, hyperoxaluria, and hypocitraturia significantly increase the risk of crystal precipitation.^4,5

Patients may also be predisposed to nephrolithiasis due to anatomical anomalies, such as ureteropelvic junction obstruction, and urinary stasis.⁶ Low fluid intake, high sodium diets, oxalate-rich foods, recurrent urinary tract infections (UTIs), and genetic predispositions increase the risk, especially in children with coexisting congenital and environmental factors.⁷

Over the last decade, percutaneous nephrolithotomy (PCNL) has become the gold standard technique for managing renal stones larger than 1 cm because of a higher stone-free rate compared to the other options, such as extracorporeal shock wave lithotripsy and retrograde intrarenal surgery.⁸ In paediatric patients, PCNL is particularly advantageous because larger stones burden can be treated efficiently in a single session. Choosing the optimal calyceal access approach can have a significant impact on surgical outcomes.⁹ The mid-calyx access (MCA) and the lower calyx access (LCA) are the sites that can be used to approach renal stone. The MCA access provides more access to multiple calyces or complex stones with spread, whereas the LCA achieves direct and directed access to stones located in the lower pole.¹⁰

Literature suggests that the MCA may require longer operative time due to its complex trajectory, while the LCA may be associated with greater risk of stone migration and technical difficulty related to infundibular angle.¹⁰ However, evidence remains limited, and this study aimed to directly compare the safety and efficacy of the MCA to the LCA. The challenge is further compounded in both paediatric cases due to smaller renal anatomy and developing structures, necessitating a more cautious and tailored approach. It will minimise the chance of complications such as bleeding or renal injury.^11,12

The study aimed to compare the safety and efficacy of these two access routes in terms of stone clearance, operative time, blood loss, postoperative complications, and length of hospital stay. This can provide local evidence for the discussed these procedures, which can help in informed surgical decision-making and improve the outcomes in paediatric urolithiasis management.

METHODOLOGY

This descriptive study was conducted on paediatric patients who underwent PCNL at the Department of Paediatric Urology, Institute of Kidney Disease, Peshawar, Pakistan, from January 2022 to October 2024. Ethical approval was obtained from the Ethical Review Committee of the Institute of Kidney Disease, Peshawar, Pakistan (502/Chairman/R&E/Committee/IKD). Patients were selected from medical records if they had undergone PCNL through either the mid or lower calyx access. The inclusion criteria were paediatric patients aged 2–15 years of either gender with Pakistan nationality, having a single-renal stone with stone size 1-3 cm located in the renal pelvis or calyces. Exclusion criteria were pyonephrosis (pus discharge on puncture), severe anatomical abnormalities of the kidney (such as horseshoe or multicystic kidney, assessed on contrast imaging or significant scarring on previous surgical site), known coagulopathies or uncorrectable bleeding disorders, and a history of previous renal surgery that could influence access site selection or complication rates.

The calculated sample size was 166 (83 per group) at 80% power and 95% confidence interval, using an operative time of 76.28 ± 34.5 minutes for the mid-calyx approach and 61.73 ± 32.35 minutes for the lower-calyx approach, as reported in a previous study.¹²

All PCNL procedures were performed under general anaesthesia by an experienced paediatric urologists. A 16 Fr single-step access sheath and a 12.5 Fr Karl Storz rigid nephroscope were used in all the patients. A double-J stent was inserted postoperatively in all the patients to ensure adequate drainage. The access site, either for the mid-calyx or the lower calyx, was determined based on stone location, surgeon preference, and individual anatomical considerations. For stones located in the upper or middle renal poles, or when a more flexible approach was needed, the mid-calyx access was typically chosen. This involved an initial puncture of the renal cortex by advancement towards the target calyx. For stones located in the lower pole, the lower calyx access was preferred, involving a more posterior and inferior puncture. These access decisions reflected the standard approach adopted by the authors, who performed many of the included procedures. These decisions were further supported by operative notes and imaging records, when available. A stone-free rate of 95% or higher was considered as a successful outcome, as determined by both endoscopic and fluoroscopic assessments during the procedure. The surgeon visually inspected the renal system with a nephroscope, while fluoroscopy was used to confirm the absence of residual stones. Operative time, started from the initial puncture to procedure completion, was recorded in minutes, including the time for stone fragmentation and placement of a nephrostomy tube or the double-J stent. Blood loss was estimated by measuring the haemoglobin drop before and after surgery, with a significant drop (greater than 2 g/dL), which was considered clinically relevant. Any need for blood transfusion was also recorded. Postoperative complications included minor bleeding (defined as bleeding which does not require any surgical intervention but is clinically significant, such as visible haematuria or mild-to-moderate haematoma), and major bleeding (which requires surgical intervention, transfusion, or embolisation). UTIs were defined by fever, positive urine cultures, and clinical signs of infection, which was treated with antibiotics and documented for infection rates. Injury to surrounding structures, including the renal pelvis, ureter, bowel, or adjacent organs, was classified as major if it required surgical repair or caused prolonged morbidity. Renal parenchymal injury, identified during the procedure or on postoperative imaging, was categorised as minor (requiring no further surgery) or major (requiring surgical repair or resulting in renal impairment). Hydronephrosis, marked by significant postoperative renal dilation or obstruction on ultrasonography one month after surgery, was managed by further intervention such as a nephrostomy tube or additional drainage proceedures. Postoperative fever—defined as a rise above 38°C within 48 hours post-surgery without evidence of infection—was assessed and treated as necessary. The length of hospital stay (measured from surgery to discharge) was recorded in days; patients were typically discharged once stable and experiencing minimal postoperative pain or complications.

Efficacy was measured by three variables: Access routes for stone clearance, operative time, and blood loss. Stone clearance was assessed by the percentage of patients achieving complete or near-complete removal (>90% stone removed confirmed on endoscope and imaging, such as non-contrast CT, KUB x-ray, or renal ultrasound). A clearance rate of ≤95% for the operated stones indicated high efficacy. Operative time—from the initial puncture to completion of the procedure, including stone fragmentation and drainage placement—was used as an indicator of efficacy, with shorter times duration associated with more effective removal. Blood loss was assessed by measuring by the change in haemoglobin levels before and after surgery.

Safety was defined as minimising adverse events and complications during and after the procedure. It was assessed by the frequency of complications, such as bleeding, UTI, renal parenchymal injury, or injury to surrounding structures including the renal pelvis or ureter. Minor bleeding, which did not require surgical intervention but needed monitoring or minor management, was also considered. Major bleeding, involving significant blood loss that required medical intervention such as transfusion, embolisation, or surgical repair, was a severe safety concern. The length of hospital stays reflected and complication and recovery. A shorter hospital stay and fewer complications were indicative of safer outcomes. Renal function was assessed through serum creatinine levels, urine output, and postoperative imaging (CT and renal scan). Elevated creatinine or reduced urine output suggested impaired kidney function, while imaging studies detected complications such as hydronephrosis or obstruction that could impact renal health.

Statistical analyses were performed using R Software version 4.1.3. The median and IQR were calculated for Skewed data, while categorical data were described in terms of frequencies and percentages. Normality was assessed through the Shapiro-Wilk test for continuous data. The Mann-Whitney U test was used to compare numerical outcomes, while the Chi-square test was used to compare categorical outcomes between the mid- and lower-calyx approaches. A p-value of <0.05 was considered statistically significant.

RESULTS

Age (p = 0.25) was normally distributed, but operation time (p <0.001) and haemoglobin drop (p = 0.045) were skewed, as assessed through the Shapiro-Wilk test.

The study compared demographic characteristics of patients with the lower (n = 115) and mid-calyx (n = 85) access. The mean age was similar between the groups (8.38 ± 3.94 vs. 8.42 ± 3.75 years, p = 0.94). Gender distribution was comparable between the groups: There were 53 (46.09%) females and 62 (53.91%) males in the lower calyx group, while and 40 (47.06%) females and 45 (52.94%) males in the mid-calyx group (p = 0.89).
 

Table  I:  Age and gender distribution in patients with the lower and mid- calyx access.

Characteristics	Lower calyx n = 115	Mid-calyx n = 85	p-values
Age, mean ± SD	8.38 ± 3.94	8.42 ± 3.75	0.94*
Gender, n (%)	-	-	0.89**
Female	53 (46.09)	40 (47.06)	-
Male	62 (53.91)	45 (52.94)	-
Age group (years), n (%)	-	-	0.59**
2-7	49 (42.61)	33 (38.82)	-
8-15	66 (57.39)	52 (61.18)	-
*Independent sample t-test; **Pearson’s Chi-squared test.

Table II: Efficacy of the mid-calyx access versus lower calyx access in paediatric percutaneous nephrolithotomy.

Characteristics	Lower calyx n = 115	Midcalyx n = 85	p-values
Stone clearance, n (%)	-	-	0.19*
Failed	18 (15.65)	8 (9.41)	-
Successful	97 (84.35)	77 (90.59)	-
Operation time (minutes), median (IQR)	54.0 (50.0, 57.5)	43.0 (41.0, 46.0)	<0.001**
Haemoglobin drop (gm/ml), median (IQR)	1.30 (0.76, 1.67)	1.31 (0.85, 1.91)	0.44
*Pearson’s Chi-squared test; **Mann-Whitney U t-test.

Table III: Safety of the mid-calyx access versus the lower calyx access in paediatric percutaneous nephrolithotomy.

Characteristics	Lower calyx n = 115	Mid-calyx n = 85	p-values
Minor bleeding	-	-	0.47
No	102 (88.70)	78 (91.76)	-
Yes	13 (11.30)	7 (8.24)	-
Major bleeding	-	-	0.46
No	112 (97.39)	81 (95.29)	-
Yes	3 (2.61)	4 (4.71)	-
Urinary tract infection	-	-	0.03
No	90 (78.26)	76 (89.41)	-
Yes	25 (21.74)	9 (10.59)	-
Injury to the surrounding structure	-	-	0.638
No	112 (97.39)	84 (98.82)	-
Yes	3 (2.61)	1 (1.18)	-
Renal parenchymal injury	-	-	>0.99
No	112 (97.39)	83 (97.65)	-
Yes	3 (2.61)	2 (2.35)	-
Postopt pyonephrosis	-	-	>0.99
No	110 (95.65)	82 (96.47)	-
Yes	5 (4.35)	3 (3.53)	-
Postopt fever	-	-	0.87
No	102 (88.70)	76 (89.41)	-
Yes	13 (11.30)	9 (10.59)	-
Serum creatinine	-	-	0.19
High	11 (9.57)	4 (4.71)	-
Normal	104 (90.43)	81 (95.29)[A1]	-
n (%); Pearson’s Chi-squared test; Fisher’s exact test.

Figure 1: Hospital stay of the mid-calyx access versus the lower calyx access group in paediatric percutaneous nephrolithotomy.

Age group analysis showed no significant differences between the groups, with 49 (42.61%) and 33 (38.82%) patients aged 2-7 years, and 66 (57.39%) and 52 (61.18%) patients aged 8-15 years in the lower and mid-calyx groups, respectively (p = 0.59, Table I).

The efficacy of the mid- and lower calyx access in PCNL was compared. Stone clearance rates were similar between the groups, with successful outcomes in 97 (84.35%) patients using the lower calyx access and 77 (90.59%) patients with the mid- calyx access (p = 0.19). Operation time was significantly shorter for the mid-calyx access compared to the lower calyx access (p <0.001). Haemoglobin drop showed no statistically significant difference between the two groups (p = 0.44, Table II).

The safety of the mid-calyx versus the lower calyx access in PCNL was assessed. Minor bleeding occurred in 13 patients (11.30%) using the lower calyx access and 7 patients (8.24%) in the mid- calyx access (p = 0.47), while major bleeding rates were similarly low in both groups (2.61% vs. 4.71%, p = 0.46). UTI was significantly lower in the mid- calyx access groups (10.59% vs. 21.74%, p = 0.03). Other complications, including injury to surrounding structures, renal parenchymal injury, pyonephrosis, and postoperative fever, were rare and not significantly different between the groups. Serum creatinine levels remained within normal limits in most patients, with no significant difference observed between groups (p = 0.19) as shown in Table III.

Hospital stay was significantly shorter for the mid-calyx access group (1.49 ± 0.22 days vs. 1.91 ± 0.77 days, p <0.001) as shown  in  Figure  1.

DISCUSSION

The aim of this study was to compare the efficacy and safety of the lower versus the mid-calyx access in paediatrics PCNL. This study focuses on demographic characteristics of the patients population, which showed no significant differences in age, gender distribution, or age group stratification between the two groups, indicating comparability of baseline characteristics. Similar findings were reported in a previous study.¹²

Efficacy analysis showed comparable stone clearance rates between the lower calyx group (84.35%) and the mid-calyx group (90.59%), with no significant difference. The operation time was nevertheless notably lower in the mid-calyx access group, indicating a possible efficiency advantage. Both approaches were not associated with any greater risk of excessive bleeding as measured by the haemoglobin drop, which is used to measure intraoperative blood loss.

The middle calyceal access was determined by Song et al. to be optimal for accessing the renal system due to its shorter and more direct cutaneous-to-pyelocaliceal pathway.¹³ This approach also facilitates precise endoscopic navigation to the inferior calyces and the proximal ureter. However, inferior calyceal access involves an oblique and extended surgical pathway, necessitating frequent nephroscopic repositioning to reach the renal pelvis. This increases the risk of parenchymal injury, as the region surrounding the inferior calyx contains a dense vascular network of arterioles.¹⁴

A diminished incidence of UTI for the mid calyx group was identified during the safety evaluation. This group displayed a potential for decreased postoperative infections. Minor and major bleeding, injury to surrounding structures, renal parenchymal injury, pyonephrosis, or postoperative fever were rare and did not differ significantly in the groups. The safety of both approaches is underscored by these findings. A previous study conducted in Iran involving 170 patients who underwent posterior subcostal single-tract complete supine PCNL with one-shot dilation compared the outcomes between the middle calyceal and the lower calyceal accesses. The middle calyceal access demonstrated favourable safety, with acceptable complication rates of 10.4% compared to the lower calyceal access, which had a slightly higher complication rate of 14.8%.¹⁵

Notably, the mid-calyx access group had a significantly shorter hospital stay, which exemplified its potential to reduce recovery time and healthcare cost. Similarly, a previous study also reported that the mean hospital stay was 1.84 days in the mid- calyx approach and 2.19 days in the lower calyx approach.¹⁵ PCNL is a safe procedure for maintaining renal function.^16,17 The renal function was preserved, and serum creatinine levels were not significantly affected in both groups. Falahatkar et al. reported no statistically significant difference in mean preoperative serum creatinine levels between the middle calyceal group (1.32 ± 0.80 mg/dL) and the lower calyceal group (1.12 ± 0.79 mg/dL) was observed.¹⁵

Ahmad et al. from Pakistan assessed the safety and efficacy of mini-PCNL in infants and reported a 90.2% stone-free rate, with only grade I complications.¹⁸ However, this study did not compare different access approaches and focus on the paediatric group under one year of age, thereby limiting its comparability to the current study’s objective of evaluating access route evaluation.

Regardless of either approach, both modalities are safe and effective. The time duration of operation in the mid calyx access may be shorter, with less frequent UTIs and starter hospital stay. These characteristic make it an efficient and effective alternative in the management of paediatric PCNL. These findings should be further evaluated in larger sample sizes and long‑term follow-up.

Additionally, the authors studied the paediatric population, whereas prior studies focused on adult patients. Nonetheless, the findings of this study support previous results in suggesting that the mid-calyceal access presents qualities such as safety, efficiency and faster recovery benefits.

This study has several limitations. It is a retrospective and non-randomised analysis conducted at a single centre, which may limit the generalisability of the findings.¹⁹ Additionally, the absence of a globally validated classification system, such as the Clavien-Dindo grading, for surgical complications in the paediatric population²⁰ posed a challenge in the standardisation and comparison of complications across studies.

CONCLUSION

Within the limitations, it can be concluded that both the mid- calyceal and the lower-calyceal access appear to be equally effective and safe for paediatric PCNL, yet the mid-calyceal access is associated with shorter operative time, reduced postoperative infection, and faster recovery. These findings should be validated with future studies using larger cohorts and longer follow-up and be used to improve the selection of paediatric PCNL access.

ETHICAL  APPROVAL:
Ethical approval was obtained from the Ethical Review Committee of the Institute of Kidney Disease, Peshawar, Pakistan (Ref. No: 502/Chairman/R&E/Committee/IKD).

PATIENTS’  CONSENT:
Informed consent was waived due to the retrospective nature of the study.

COMPETING  INTEREST:
The  authors  declared  no  conflict  of  interest.

AUTHORS’  CONTRIBUTION:
AK:  Conception  and  drafting.
AN,  RAK:  Data  acquisition  and  drafting.
NU:  Data  interpretation  and  critical  revision.
SUR:  Data  analysis  and  drafting.
KJ:  Data  curation  and  drafting.
All authors approved the final version of the manuscript to be published.

REFERENCES

1. Hernandez JD, Ellison JS, Lendvay TS. Current trends, evaluation, and management of paediatric nephrolithiasis. JAMA Pediatr 2015; 169(10):964-70. doi: 10.1001/jama paediatrics.2015.1419.
2. Liu Y, Chen Y, Liao B, Luo D, Wang K, Li H, et al. Epide-miology of urolithiasis in Asia. Asian J Urol 2018; 5(4): 205-14. doi: 10.1016/j.ajur.2018.08.007.
3. Almusafer M, Issa H, Paraskevopoulou ME, Symeonidis EN, Bhatti KH, Moussa M, et al. Unveiling the burden of nephrolithiasis in low-and lower-middle income countries: A review on its presentation, risk factors, treatment practices, and future directions. Soc Int Urol J 2024; 5(5): 361-70. doi: 10.3390/siuj5050055.
4. Meyers AM, Naicker S. Nephrolithiasis (part 1): Epide-miology, causes and pathogenesis of recurrent nephroli-thiasis. South African Med J 2021; 111(10):930. doi: 10.7196/samj.2021.v111i10.15988.
5. Wigner P, Grębowski R, Bijak M, Szemraj J, Saluk-Bijak J. The molecular aspect of nephrolithiasis development. Cells 2021; 10(8):1926. doi: 10.3390/cells10081926.
6. Saadeh SA. Paediatric nephrolithiasis: Risk factors, evaluation, and prevention. Pediatr Ann 2020; 49(6): e262-7. doi: 10.3928/19382359-20200518-01.
7. Allam EA. Urolithiasis unveiled: Pathophysiology, stone dynamics, types, and inhibitory mechanisms: A review. African J Urol 2024; 30:34. doi: 10.1186/s12301-024-00 436-z.
8. Hatwar G, Dhale A, Dharamshi JD, Pendkar R. Comparative analysis of standard percutaneous nephrolithotomy (PCNL) and mini-percutaneous nephrolithotomy (Mini-PCNL) for renal stones larger than 2 cm at a rural hospital: A study protocol. Cureus 2024; 16(6):e61963. doi: 10.7759/ cureus.61963.
9. Peng T, Zhong H, Hu B, Zhao S. Minimally invasive surgery for paediatric renal and ureteric stones: A therapeutic update. Front Pediatr 2022; 10:902573. doi: 10.3389/fped. 2022.902573.
10. Caglayan V, Onen E, Avci S, Kilic M, Sambel M, Oner S. Percutaneous nephrolithotomy via a middle calyx access is effective in the treatment of lower pole kidney stones: A single-centre study. Urol Int 2020; 104(9-10):741-5. doi: 10.1159/000505081.
11. Pais P, Wightman A. Addressing the ethical challenges of providing kidney failure care for children: A global stance. Front Pediatr 2022; 10:842783. doi: 10.3389/fped.2022. 842783.
12. Deger M, Izol V, Ok F, Bayazit Y, Satar N, Aridogan IA. Comparison of efficacy and safety of isolated single different calyx accesses in percutaneous nephrolithotomy. J Urol Surg 2019; 6(4):289-94. doi: 10.4274/jus.galenos. 2019.2858.
13. Song Y, Jin W, Hua S, Fei X. Middle calyx access is better for single renal pelvic stone in ultrasound-guided percutaneous nephrolithotomy. Urolithiasis 2016; 44(5): 459-63. doi: 10.1007/s00240-016-0866-9.
14. Tan J, Chen B, He L, Yin G, Jiang Z, Yao K, et al. Renal access through the inferior calyx is associated with higher risk of severe bleeding after percutaneous nephroli-thotomy. Archiv Med Sci 2015; 11(2):340-5. doi: 10.5114/ aoms.2015.50966.
15. Falahatkar S, Kazemnezhad E, Moghaddam KG, Kazemzadeh M, Asadollahzade A, Farzan A, et al. Middle calyx access in complete supine percutaneous nephro-lithotomy. Canad Urol Assoc J 2013; 7(5-6): E306-10. doi: 10.5489/cuaj.11307.
16. Eslahi A, Ahmed F, Hosseini MM, Rezaeimehr MR, Fathi N, Nikbakht HA, et al. Minimal invasive percutaneous nephrolithotomy (Mini-PCNL) in children: Ultrasound versus fluoroscopic guidance. Arch Ital Urol Androl 2021; 93(2): 173-7. doi: 10.4081/aiua.2021.2.173.
17. Dogan HS, Asci A, Kahraman O, Gasimov K, Bozaci AC, Tatanis V, et al. Comparison of efficiency and safety of retrograde intrarenal surgery and micropercutaneous nephrolithotomy in paediatric kidney stones smaller than 2 cm: A prospective cohort study. J Endourol 2021; 35(8):1124-9. doi: 10.1089/end.2020.0624.
18. Ahmad T, Minallah N, Khaliq N, Rashid H, Syed M, Almuradi MAA. Safety and efficacy of minimally invasive percu-taneous nephrolithotomy for infantile nephrolithiasis. Single centre experience from Pakistan. Front Pediatr 2023; 10:1035964. doi: 10.3389/fped.2022.1035964.
19. Das MK. Multi-centre studies: Relevance, design and implementation. Indian Pediatr 2022; 59:571-9. doi: 10. 1007/s13312-022-2561-y.
20. Golder H, Casanova D, Papalois V. Evaluation of the usefulness of the Clavien-Dindo classification of surgical complications. Cir Esp (Engl Ed) 2023; 101(9):637-42. doi: 10.1016/j.cireng.2023.02.002.