Correction: Outcomes of nephrostomy and double J stent in malignant ureteral obstruction in the Palestinian practice

Correction: Ghannam et al. BMC Urology 24, 245 (2024)

https://doi.org/10.1186/s12894-024-01640-3

Following publication of the original article [1], the following errors were reported.

The original article has been corrected.

Section and Paragraph	Incorrect text (Highlighted)	Correct text
Abstract	Background Malignant ureteral obstruction (MUO) is a serious health condition in which a malignant tumor compresses the ureter. The optimal decompressive intervention in MUO remains unclear. This study was conducted to assess and compare renal function, the occurrence of ureterohydronephrosis (UHN), intraoperative, and postoperative complications among patients with MUO who underwent double J stenting (DJS) and percutaneous nephrostomy (PCN) in the Palestinian practice. Methods This study was conducted in retrospective design in one of the main tertiary care hospitals in the West Bank of Palestine. The data were collected from the electronic health information system of the hospital for the patients with MUO who received either DJS or PCN as a decompressive intervention from January 2018 to January 2024.	Updated corrections Background and Methods should be: Background: Malignant ureteral obstruction (MUO) is a serious condition in which a malignant tumor compresses the ureter. The optimal decompressive intervention for MUO remains unclear. This study was conducted to assess and compare renal function, the occurrence of ureterohydronephrosis (UHN), intraoperative, and postoperative complications among patients with MUO who underwent double J stenting (DJS) and percutaneous nephrostomy (PCN) in clinical practice in Palestine. Methods: This study was conducted using a retrospective design at one of the main tertiary care hospitals in the West Bank of Palestine. The data were collected from the hospital’s electronic health information system for patients with MUO who received either DJS or PCN as a decompressive intervention between January 2018 and January 2024.
Abstract	Conclusion Despite improvements in renal functions, creatinine and BUN levels remained abnormal even after receiving a decompressive intervention. Postoperative complications were frequently reported among patients who received DJS or PCN as decompressive interventions. Larger prospective studies are still needed to determine the optimal interventions to improve outcomes, quality of life, and survival rates of patients with DJS or PCN.	Revised Conclusion should be: Conclusion: Renal function improved following intervention, although creatinine and BUN levels often remained abnormal, and postoperative complications were common. No statistically significant differences were observed between the two procedures; however, these findings should be interpreted with caution given the small sample size, baseline imbalances, and lack of multivariable adjustment. Larger multicenter prospective studies with standardized benchmarks, survival, and quality-of-life outcomes are needed to more reliably determine the comparative effectiveness of DJS and PCN.
Background	First paragraph of the Background heading needs to be revised. Malignant ureteral obstruction (MUO) is a serious health condition in which a malignant tumor compresses the ureter [1]. MUO can be caused by malignancy in the urothelium of the ureter or metastasis from other pelvic malignancies. Moreover, compression can be caused by retroperitoneal/pelvic lymphadenopathy or retroperitoneal fibrosis induced by either surgery, chemotherapy, radiotherapy, or a combination of these treatment modalities [2–4]. Patients with MUO often spend a prolonged time in the hospital and have a median survival period between 3 and 7 months following diagnosis [3]. Management of MUO is challenging and unclear [2, 3].	The corrected paragraph should be: Malignant ureteral obstruction (MUO) is a serious condition in which a malignant tumor compresses the ureter [1]. MUO can be caused by malignancy in the urothelium of the ureter or metastasis from other pelvic malignancies. Moreover, compression can occur due to retroperitoneal/pelvic lymphadenopathy or retroperitoneal fibrosis induced by either surgery, chemotherapy, radiotherapy, or a combination of these treatment modalities [2–4]. Patients with MUO often experience prolonged hospital stays and have a median survival period between 3 to 7 months following diagnosis [3]. Management of MUO remains challenging and not well defined [2, 3].
Background	Paragraph begins with “So far, there is no specific ………… PCN in the Palestinian practice.” needs to be updated.	Corrected Paragraph should be: Although comparative evidence between DJS and PCN in MUO has been synthesized in recent meta-analyses [3, 17], these investigations largely reflect data from high-volume centers outside the Middle East. The transferability of such findings to resource-constrained and region-specific practices remains uncertain. In Palestine and neighboring countries, systematically reported outcomes of decompressive interventions in MUO are scarce. Differences in patient demographics, cancer epidemiology, health system infrastructure, and access to interventional radiology may substantially influence both the feasibility and effectiveness of DJS and PCN. Context-sensitive evidence is therefore essential to guide local clinical decision-making, optimize resource allocation, and improve patient care in this under-represented region. To date, no decompressive intervention has been demonstrated to be superior in the management of MUO within the Palestinian practice. Outcomes of PCN and DJS, including renal function, complication profiles, and survival, have not been systematically compared in this setting. This study was thus undertaken to evaluate and contrast renal function, occurrence of ureterohydronephrosis (UHN), and intra- and postoperative complications among patients with MUO who underwent DJS or PCN in a major tertiary hospital in Palestine.
Methods	In the section heading “Study design and setting,” the following sentence needs to be revised: “The study was conducted in one of the main tertiary care hospitals in the West Bank of Palestine.”	Revised sentence should be: It was carried out at one of the main tertiary care hospitals in the West Bank of Palestine.
Methods Decompressive interventions	The first paragraph of the section titled “Decompressive interventions” under the “Methods” heading needs to be revised.	In our center, the choice between DJS and PCN was influenced by patient and disease characteristics documented at presentation. DJS was generally attempted in patients with unilateral obstruction, moderate UHN, and upper or mid‑ureteral involvement, particularly when cystoscopic or fluoroscopic access was technically feasible. PCN was more frequently selected for patients with bilateral or severe UHN, lower ureteral obstruction, or bulky pelvic malignancies such as bladder or prostate cancer, where retrograde stent placement was less likely to succeed. In addition, PCN was favored when rapid decompression was required under local anesthesia or when retrograde stenting attempts had failed. The final decision was made by the treating urologist in consultation with the oncology team, taking into account anatomical feasibility, cancer type and stage, comorbidities, and patient preference.
Reference	Reference 21 is cited in the following sentence within the “Data collection and study variables” section: “Categorical variables included gender……. serum blood urea nitrogen (BUN) prognosis”	Categorical variables included gender, cancer type, presence of comorbidities, cancer management, side of UHN, anatomical laterality, ureteral intraluminal lesion, type of decompressive intervention, type of anesthesia, radiological guidance, intraoperative and postoperative complications, Clavien-Dindo grade of postoperative complications [21], need for intensive care unit (ICU), cancer stage, degree of UHN, level of ureteral obstruction, UHN prognosis, serum creatinine prognosis, and serum blood urea nitrogen (BUN) prognosis.
Tables	Missing footnote for the Tables 1, 3 and 4	Table 1 Footnote: DJS: double J stenting, PCN: percutaneous nephrostomy Table 3 Footnote: DJS: double J stenting, UHN: ureterohydronephrosis, PCN: percutaneous nephrostomy Table 4 Footnote: DJS: double J stenting, UHN: ureterohydronephrosis, PCN: percutaneous nephrostomy, *Duration of the interventional procedure refers to the time from when the patient enters the operating room until they leave the recovery room, **The duration of interventional procedure patency refers to the length of time a decompressive intervention remains effective or functional
Results Occurrence of ureterohydronephrosis (UHN)	The last sentence of the section titled “Occurrence of ureterohydronephrosis (UHN)” under the “Results” heading. The sentence currently reads: “These details are shown in Table 3.”	Overall, patients managed with PCN presented with more severe disease characteristics (bilateral and severe UHN, lower ureteral obstruction), whereas those managed with DJS more often had unilateral and moderate obstruction. These details are shown in Table 3.
Results Complications and outcomes of the decompressive interventions	Include the text “Clavien Dindo grade of postoperative complications” in the sentence beginning with “There were no statistically significant…… creatinine and BUN levels.” This sentence is located within the “Complications and outcomes of the decompressive interventions” section under the Results heading.	Updated sentence should read as: There were no statistically significant differences between DJS and PCN in the occurrence of intraoperative complications, postoperative complications, Clavien-Dindo grade of postoperative complications, time from intervention to diagnosis of complications, ICU admission, UHN prognosis, or postoperative serum creatinine and BUN levels.
Discussion Limitations of the study	The paragraphs within the “Limitations of the study” section heading need to be revised.	Revised ‘Limitations of the study’ should read as: Limitations of the study The findings of this study should be interpreted with caution in light of several methodological limitations. First, the retrospective design is inherently vulnerable to missing data, incomplete documentation, and unmeasured confounding, which may have influenced both exposure and outcome classification. Second, this was a single-center analysis conducted at the largest tertiary hospital in the West Bank that routinely performs decompressive interventions for MUO; while this enhances procedural consistency, it restricts external validity and provides a context-specific view that may not generalize to other institutions or health systems. Third, the sample size was relatively small, which limits statistical power, increases the risk of type II error, and reduces the precision of estimates compared with larger meta-analyses. Fourth, it is important to note that our findings did not demonstrate statistically significant differences in procedural time or complication rates between DJS and PCN. This contrasts with prior meta-analyses [3, 17], which reported shorter procedural times and fewer device dislodgments with stents. The discrepancy may be explained by the relatively small sample size of our cohort, the retrospective single-center design, and the absence of statistical adjustment for confounding factors such as cancer stage, anatomical laterality, and anesthesia type. These methodological constraints likely limited our ability to detect differences observed in larger, multicenter analyses. Therefore, our results should be interpreted with caution and considered hypothesis-generating rather than definitive. Fifth, there was no randomization or control group, and no statistical adjustment for confounding factors (e.g., cancer type and stage, bilateral versus unilateral obstruction, performance status, baseline renal function, and infection status). Another important limitation was the potential for selection bias. In clinical practice, the choice between DJS and PCN is often guided by preoperative factors such as tumor location, size, degree of obstruction, and anticipated technical feasibility. As a result, the two groups in our study were not fully comparable at baseline, for example, patients with lower ureteral obstruction were more frequently managed with PCN. Furthermore, not all patients with MUO and UHN necessarily require decompressive intervention. Given the limited survival associated with advanced malignancy, the decision to place a stent or nephrostomy tube should be individualized, weighing potential benefits against quality-of-life considerations and patient preference. Because survival and patient-reported outcomes were not systematically captured in this retrospective study, our findings cannot determine the appropriateness of decompression in all cases and should be interpreted with caution. In addition, the PCN and DJS groups differed significantly in baseline characteristics, including laterality, severity of UHN, and level of obstruction. Because of the limited sample size, no statistical adjustment for these differences was feasible. As a result, observed similarities or differences in outcomes may partly reflect underlying patient selection rather than the intrinsic properties of the procedures. Because of the retrospective design and limited sample size, we were unable to perform meaningful subgroup stratification or apply advanced statistical adjustments to account for these differences. Consequently, comparisons of intraoperative and postoperative complications between groups should be interpreted with caution, as they may reflect underlying patient characteristics rather than the intrinsic properties of the procedures themselves. Sixth, patient-reported outcomes (pain, discomfort, satisfaction, and quality of life) were unavailable due to the retrospective nature of data capture, precluding assessment of the comparative burden and acceptability of DJS versus PCN. Moreover, this study did not evaluate survival outcomes, which represent a critical endpoint in patients with malignant ureteral obstruction. Without survival analysis, the long-term prognostic implications of decompressive interventions cannot be determined. Finally, outcomes were not analyzed across standardized follow-up intervals, limiting evaluation of durability, late complications, and survival. Future research should employ multicenter, prospective designs with larger samples, prespecified covariates, and robust statistical modeling (e.g., multivariable regression, propensity score methods, or instrumental variable approaches), alongside systematic collection of patient-reported outcomes and time-anchored follow-up, to more reliably determine the comparative effectiveness of DJS and PCN in malignant ureteral obstruction.
Conclusion	The paragraph within the “Conclusion” section heading need to be revised.	Revised ‘Conclusion’ should read as: Conclusion In this single-center retrospective study, both DJS and PCN were used to decompress MUO. Renal function improved following intervention, although creatinine and BUN levels often remained abnormal. Postoperative complications were common across both procedures. While no statistically significant differences were observed between DJS and PCN in terms of intraoperative or postoperative complications, ICU admission, or renal function parameters, these findings should be interpreted with caution given the small sample size, baseline imbalances, and absence of multivariable adjustment. Rather than establishing equivalence, our results provide descriptive evidence of current practice in Palestine and highlight the need for larger, multicenter prospective studies with standardized benchmarks, survival endpoints, and quality-of-life measures to more reliably determine the comparative effectiveness of DJS and PCN in MUO.

In Table 5 of this article [1], the entries for ‘Clavien-Dindo grade of postoperative complications’ was mistakenly omitted. Now it has been updated to the article. Revised table is shown below:

Table 5.

Complications and outcomes of the decompressive interventions

	Procedure
	DJS	PCN	Total
Variable	n (%)	n (%)	N (%)	p-value
Preoperative serum creatinine level
Normal	12 (19.4)	8 (12.9)	20 (32.3)	0.001
Abnormal	7 (11.3)	35 (56.5)	42 (67.7)
Preoperative serum BUN level
Normal	12 (19.4)	11 (17.7)	23 (37.1)	0.009
Abnormal	7 (11.3)	32 (51.6)	39 (62.9)
Postoperative serum creatinine level (report 1)
Normal	10 (16.1)	9 (14.5)	19 (30.6)	0.012
Abnormal	7 (11.3)	32 (51.6)	39 (62.9)
Postoperative serum creatinine level (report 2)
Normal	10 (16.1)	7(11.3)	17 (27.4)	0.004
Abnormal	5 (8.1)	26 (41.9)	31 (50.0)
Postoperative BUN level (report 1)
Normal	11 (17.7)	8 (12.9)	19 (30.6)	0.006
Abnormal	6 (9.7)	26 (41.9)	32 (51.6)
Postoperative BUN level (report 2)
Normal	10 (16.1)	9 (14.5)	19 (30.6)	0.027
Abnormal	5 (8.1)	21 (33.9)	26 (41.9)
Postoperative BUN level (report 3)
Normal	9 (14.5)	7 (11.3)	16 (25.8)	0.043
Abnormal	4 (6.5)	15 (24.2)	19 (30.6)
Intraoperative complications
No	18 (29.0)	42 (67.7)	60 (96.8)	0.522
Yes	1 1.6)	1 (1.6)	2 (3.2)
Postoperative complications
No	9 (14.5)	17 (27.4)	26 (41.9)	0.589
Yes	10 (16.1)	26 (41.9)	36 (58.1)
Type of postoperative complications
Stent migration/slip	4 (6.5)	17 (27.4)	21 (33.9)	0.387
UTI and urosepsis	3 (4.8)	4 (6.5	7 (11.3)
Stent obstruction	0 (0.0)	2 (3.2)	2 (3.2)
Stent discomfort	1 (1.6)	1 (1.6)	2 (3.2)
Failure	1 (1.6)	1 (1.6)	2 (3.2)
UTI, urosepsis, and stent migration/slip	1 (1.6)	0 (0.0)	1 (1.6)
Obstruction and UTI	0 (0.0)	1 (1.6)	1 (1.6)
Clavien-Dindo grade of postoperative complications
Grade I (minor, no intervention)	1 (1.6)	2 (3.2)	3 (4.8)	0.060
Grade II (pharmacological treatment, e.g., antibiotics for UTI)	3 (4.8)	3 (4.8)	6 (9.7)
Grade IIIa (intervention without general anesthesia, e.g., stent repositioning)	2 (3.2)	0 (0.0)	2 (3.2)
Grade IIIb (intervention under general anesthesia)	4 (6.5)	18 (29.0)	22 (35.5)
Grade IV (life-threatening, ICU admission)	0 (0.0)	3 (4.8)	3 (4.8)
Grade V (death)	0 (0.0)	0 (0.0)	0 (0.0)
Time from receiving the decompression intervention to the diagnosis of complications (days)
< 30	6 (9.7)	12 (19.4)	18 (29.0)	0.388
≥ 30	4 (6.5)	14 (22.6)	18 (29.0)
ICU admission
No	19 (30.6)	40 (64.5)	59 (95.2)	0.326
Yes	0 (0.0)	3 (4.8)	3 (4.8)
Prognosis of UHN
Deteriorated	0 (0.0)	4 (0.0)	4 (6.5)	0.429
No change	3 (4.8)	5 (4.8)	8 (12.9)
Improved	10 (16.1)	15 (16.1)	25 (40.3)
Serum creatinine prognosis
Deteriorated	6 (9.7)	7 (11.3)	13 (21.0)	0.142
No change	6 (9.7)	11 (17.7)	17 (27.4)
Improved	5 (8.1)	23 (37.1)	28 (45.2)
Serum BUN prognosis
Deteriorated	7 (11.3)	6 (9.7)	13 (21.0)	0.063
No change	4 (6.5)	7 (11.3)	11 (17.7)
Improved	6 (9.7)	25 (40.3)	31 (50.0)

BUN Blood urea nitrogen, DJS Double J stenting, ICU Intensive care unit, UHN Ureterohydronephrosis, UTI Urinary tract infection, PCN Percutaneous nephrostomy.