Retrorenal Colon Research Articles

Comparison of supine-prone percutaneous nephrolithotomy methods in the treatment of kidney stones in pediatric patients: prospective randomized study.

Mini-PCNL is one of the most effective surgical methods in the treatment of kidney stones in pediatric patients. In this study, we aimed to compare PCNL in the supine-prone position in pediatric patients (especially operation time, postop complications, hospital stay and stone-free rates).We conducted our study in a randomized and prospective manner. Patients with lower pole stones larger than 1cm, stones larger than 1.5cm in the pelvis, upper pole, midpole or multiple locations, and patients who did not respond to ESWL or whose family that preferred mini-PCNL to be the primary treatment were included in the study. Patients with any previous kidney stone surgery, patients with coagulation disorders and patients with retrorenal colon were excluded from the study. Between 2021 and 2023, a total of 144 patients underwent PCNL. 68 of these patients had supine PCNL and 76 prone PCNL. Postoperative Clavien grade1 complication occurred in a total of 7 patients in the prone position; Clavien grade1 complication occurred in 1 patient in the supine position. The mean operation time for prone PCNL was 119.88 ± 28.32min, and the mean operative time for supine PCNL was 98.12 ± 14.97 the mean hospitalization time in prone PCNL was 3.56 ± 1.12days, and 3.00 ± 0.85days in supine PCNL. In conclusion, supine PCNL is a safe and effective method in the treatment of pediatric kidney stones and postoperative complications were observed to be less; the operation time and hospital stay were shorter in supine PCNL.

Occurrence of Retrorenal Colon in the Indian Population – A Significant Finding from Urological Perspective

Introduction: Ascending and descending coli normally are located anterolateral to kidneys. Retrorenal position of the colon has a reported prevalence of 10%–20% in the general population. Its occurrence is of significant while performing percutaneous nephrolithotomy (PNL) which is a routine management procedure for patients showing clinical disease associated with renal calculus. PNL in patients with retrorenal colon can lead to colonic perforation which is associated with significant morbidity and mortality related to septicemia, peritonitis, formation of abscess, and nephro-colic and/or colo-cutaneous fistulae. Hence, the preoperative information about the presence of retrorenal colon is essential for the prevention of surgical complications. Materials and Methods: Our retrospective study included patients who underwent computed tomography (CT)/magnetic resonance (MR) abdomen in our department of radiodiagnosis. All the scans were evaluated for the presence of retrorenal colon. The persistence of retrorenal colon was also observed with change in posture among those with prone scans. Results: The retrorenal colon was present in 130 out of 669 patients included in the study, with an occurrence rate of nearly 20%. Alteration in the position of retrorenal colon was noted with prone position in approximately 79%. Conclusion: The occurrence of retrorenal colon is high in the Indian population being approximately 20% without change with prone position in one-fifth. Thus, to reduce the risk of complication related to colonic perforation during PNL, all patients must be subjected to CT/MR abdomen to detect retrorenal colon followed by scan in the prone position, if retrorenal colon is present, to evaluate the alterations in colonic position with prone posture.

Prevalence of the Retro-Renal Colon: A Systematic Review and Meta-Analysis with Implications for Percutaneous Nephrolithotomy.

This systematic review and meta-analysis aims to determine the prevalence of the retrorenal colon (RRC) and its implications in percutaneous nephrolithotomy with the overall objective of promoting the prevention of associated iatrogenic complications. A systematic search of literature was conducted on the electronic databases PubMed, ScienceDirect, and Hinari to identify studies eligible for inclusion. Search results were screened by title and abstract, and those potentially relevant were evaluated by full text. Studies were deemed eligible for inclusion if they reported clear extractable data regarding the prevalence of the retro-renal colon. A meta-analysis was completed using MetaX1 to calculate the pooled prevalence of the retro-renal colon. Sub-group analysis was performed based on geographical regions from which the studies originated, imaging modality, and patient position. 174 records were screened and a total of 10 records included in the analysis with retrospective cohort studies being the most common study design. A male predominance was seen in most sample sizes that had reported data on gender demographics ranging from 41.5-62%. The most common imaging modality utilized was computerized tomography (CT) scan followed by ultrasound. The range of the unweighted prevalence of retro-renal colon across all studies that had absolute numbers reported was from 3.5-25%. One of the studies reported a colonic perforation rate of 0.3% in patients without CT images. The retro-renal colon is a relatively common finding with observed preponderance to females and left lateralization. The presence of RRC increases the likelihood of colon perforations while gaining percutaneous access to the kidney. Pre-procedural imaging can help detect its presence and choose an appropriate route of entry. USG and CT have both been found useful as a modality to pick up RRC.

Ultrasound-guided percutaneous nephrolithotomy in patients with retrorenal colon: a single-center experience.

Retrorenal colon is a risk factor for colonic injury during percutaneous nephrolithotomy (PCNL). Our aim in this study is to report the feasibility and outcomes of ultrasound-guided percutaneous nephrolithotomy in patients with preoperatively known retrorenal colon by cross-sectional imaging. In this prospective study, all patients with large renal stones and retrorenal colon in preoperative cross-sectional imaging from September 2020 to January 2022 who were candidates for PCNL were enrolled. Percutaneous access was established by ultrasonography guidance by the freehand method with dilation of the tract by a combination of fluoroscopy and ultrasonography. Of the 1123 patients (Male = 760 and Female = 363) who underwent PCNL, 13 patients (Male = 6 and Female = 7) had retrorenal colon in the preoperative computed tomography. The series included two patients with malrotated kidneys. Complete stone clearance was achieved in 11 patients. Patients were followed up for at least 3months. No serious postoperative complications were observed during follow-up. In selected patients and experienced hands, ultrasound-guided PCNL can be an alternative option for the treatment of patients with large renal stones who have retrorenal colon in cross-sectional imaging.

Retrorenal colon in pediatric patients with urolithiasis: Is the supine position for PCNL advantageous?

Percutaneous nephrolithotomy (PCNL) is one of the main approaches for the treatment of large and complex stones in pediatric patients. The patient position for PCNL has been classically divided into prone or supine and the prone position is more commonly used. One of the most feared complications of this surgical technique is colon injury and the objective of this work is to evaluate the incidence of retrorenal colon (RRC) both supine and prone position, in pediatric patients, through radiological images. A retrosepctive review was performed of all abdominal CT scans performed in one center, in patients under 18 years since 2017 to 2019. The ideal path for percutaneous puncture was traced in the upper, middle, and lower calyces of both kidneys in the prone and supine positions and contact with the kidney and adjacent organs was evaluated, with a uro-radiologist. Chi-square test and Student's t test were applied. 50 CT-scans were performed on 44 children. Patients had a mean age of 12.6 years and 71.4% were male. Twenty-five scans were performed in the prone and 25 in the supine position. The incidence of RRC for the left kidney (LK) was significantly higher in the lower calyx in prone position than in the supine position, 28% vs 4% (p=0.049), and the right kidney (RK) presented RRC only in the prone position. The liver was the most frequent retrorenal organ (97.7%) for the RK, with a non-significant difference by position, while for the LK the spleen was the most frequent (61.1%). Colon injury is one of the most morbid complication in PCNL and one of the reasons to perform a CT scan before surgery, on which its incidence appears to be <1% in adults. The present study revealed RRC to be present in three (12%) patients in the supine position and seven (28%) patients in the prone position (p=0.15). These results were slightly higher from those reported in adults (supine: 1.7%-10%; prone: 6.8%-20%), but there are no reports in the literature on this issue to allow appropriate comparison. This is the first study to attempt to assess the incidence of RRC in children according to position. The incidence of RRC for an ideal puncture was significantly higher in the lower calyx of the left kidney in the prone position than in the supine position, and in the right kidney, the RRC only occurred in the prone position.

Anatomical Variation of Colon Detected on Abdominal Computed Tomography Correlated with Gender

Introduction: Anatomical variation of the colon can cause diagnostic dilemmas and pose a problem while radiological interpretation and during various procedures. Radiologists and clinicians should exert much caution during the procedures in such patients. This study was done to study the anatomical variation of the colon in abdominal CT scans and correlated the variations with gender. &#x0D; Methods: It was a cross-sectional study done at the Department of Radiology and Imaging of Manipal Teaching Hospital from September 2020 to March 2021. Abdominal CT was obtained and colonic position was evaluated. The Chi-square test was applied to assess the correlation between colonic variations and gender.&#x0D; Results: There were 388 patients in total. The age of the patients ranged from 3 years to 94 years. The mean age of the patients was 44.8±18.6 years. There were 166 (42.8%) females and 222 (57.2 %) males. Out of 388 patients, 170(43.8) had some colonic anatomical variations. Sixteen (4.1%) patients had retro gastric colon. Around 6% had a right retrorenal colon and 30(7.7%) had a left retrorenal colon. Seven (1.8%) patients had anterolateral hepatodiaphragmatic interposition. Forty-two patients (10.8%) had high positioned caecum. The redundant sigmoid colon was present in 38(9.8%) patients. There was no significant correlation between the colonic variation and gender.&#x0D; Conclusion: Different variations in the colon exist even in the Nepalese population, of which the radiologists, as well as the surgeons, should be aware.

Incidence of posterolateral and retrorenal colon in supine and prone position in percutaneous nephrolithotomy.

Colon injury is a distressing complication during percutaneous nephrolithotomy (PCNL). Posterolateral colon (PLC) and retrorenal colon (RRC) are known to be the risk factors of colonic injury during PCNL. We evaluated the incidence of PLC and RRC in both supine and prone position of patients who underwent PCNL in our institution, and determined the risk factors of PLC and RRC through a review of computed tomography (CT) scan. To define PLC and RRC, we divided kidney into anterior, anterolateral, posterolateral and retrorenal zone by drawing three parallel lines in the CT scan. Among a total of 102 patients, PLC and RRC were identified in 16 (15.7%) cases in supine, and 25 (24.5%) cases in the prone position. PLC and RRC were most frequently present in the upper and lower pole of the left kidney in prone position compared to supine (p value less than 0.001). Risk factors of PLC and RRC in the prone position were old age (over 68), lower body mass index (BMI), and thinner perirenal fat layer. Therefore, an initial percutaneous puncture in PCNL needs to be carefully accessed to those patients with such high risks of colon injury.

A Different and Novel Alternative (ADANA) Renal Access Technique when CT or USG Guidance Is Inadequate in Case of Retro-Renal Colon

Introduction: Computed tomography (CT) or ultrasonography (USG)-guided renal access for percutaneous nephrolithotomy (PNL) is not suitable in all cases with retro-renal colon (RRC) due to anatomical and technical restrictions. We would like to describe our novel technique that permits standard subcostal renal access with a small incision for these patients. Methods: This method was performed on adult patients with severe RRC and complex renal stones who were not suitable for renal access with CT or USG guidance. Time from skin incision to puncture needle insertion, incision length, stone-free rate (SFR), and complications were evaluated. Surgical Technique: The appropriate renal calyx for renal access was identified with retrograde pyelography. The skin closest to the identified calyx was incised and retroperitoneum visualized. The RRC was swept laterally by blunt dissection to obtain a safe puncture line. The retractors were placed to keep the colon away from the incision. Then, the puncture needle was placed over Gerota’s fascia. After this, the puncture needle was inserted into the targeted calyx under fluoroscopic guidance. The insertion of guidewire and the rest of the procedure such as dilatation and insertion of Amplatz sheath were performed under same maneuver. Results: A total of 1,348 patients were treated with PNL between January 2016 and November 2019. Our group consisted of 16 adult patients with a median age of 44.8 years (7 females and 9 males) who underwent PNL with our new access technique. SFR and clinically insignificant residual fragment (CIRF) rate were 72.5 and 14.2%, respectively. The median access time was 22.2 min (range: 15–30 min). The median skin incision length was 3.7 (range: 3.0–4.5) cm. The average skin incision length was 3.7 cm. The SFR and CIRF rate were 72.5 and 14.2%, respectively. We did not observe any complication related to our access technique. Conclusion: Our novel access technique created a safe anatomical route for standard subcostal renal access with acceptable incision length and very low complication rate.

Ultrasonographic Detection of Retrorenal Colon in Prone Position: An Alternative to Computed Tomography

ObjectiveTo evaluate the correlation between ultrasonography (US) and computed tomography (CT) in prone position to detect retrorenal colon (RRC). Materials and MethodsIn this prospective study, we included 310 patients who presented to our clinic between April 2017 and June 2019. All patients were evaluated for RRC with US and CT in prone position. Kappa compliance coefficient (κ) was used to express the compliance between CT and US outcomes. ResultsThis study included 119 (38%) female and 191 (62%) male patients with a mean age of 44.5 ± 16.1 years. With both CT and US, RRC was detected in a total of 42 (13.5%) patients. RRC was found in 9 patients (8%) on the right side, in 32 patients (18%) on the left side and in 1 patient on both sides with CT (P = .036). However, with US, it was detected in 10 patients (8%) on the right, in 31 patients on left side and in 1 patient on both sides (P = .083). The RRC detection compliance coefficients were excellent between US and CT (κ: 0.945). ConclusionUS used in prone position is a suitable and practical imaging alternative to CT for detection of RRC.

Retrorenal Colon Detection Before Percutaneous Nephrolithotomy Surgery Does Not Reduce the Probability of Iatrogenic Colon Injury

Retrorenal Colon Detection Before Percutaneous Nephrolithotomy Surgery Does Not Reduce the Probability of Iatrogenic Colon Injury

The risk factors associated with colonic injury during percutaneous renal stone surgery – a literature review

Objective: A focused literature review was conducted of colonic injuries occurring during percutaneous nephrolithotomy (PCNL) procedures to determine the importance of patient position, identifiable risk factors and methods to avoid colonic injury. Method: A MEDLINE literature search was performed from PubMed and Scopus databases to retrieve all articles relating to colonic injuries occurring during PCNL. Incidence of colonic injury, patient management, position, side of stone and recognised risk factors were compiled for analysis. Results: Of the 35,054 PCNLs carried out, 87 colonic perforations were identified, which results in a 0.25% chance of perforation. A total of 65.5% (57/87) of colonic perforations occurred during left-hand punctures, and 54.0% (47/87) occurred in the prone position. Retrorenal colon, posterior colon, previous renal tract surgery, horseshoe kidney and mobile kidneys were the most common risk factors identified. Discussion: The risk of colonic perforation during PCNL was 0.25% across these studies. It more commonly occurred in the prone position and on the left-hand side. Only four perforations were noted to be in the supine position. A retrorenal colon is implicated as the most common identifiable risk factor. Careful preoperative work-up, planning and intraoperative use of ultrasound combined with fluoroscopy is the best method of preventing a colonic injury. Level of evidence: Not applicable for this multicentre audit.

Percutaneous nephrolithotomy: implementation of digital insertion and dissection as an adjunct to the technique

BACKGROUND: Percutaneous nephrolithotomy (PCNL) was established as a minimally invasive treatment option for kidney stones in the 1970s and is considered a safe and effective procedure, with stone clearance rates of 78-95%. The ideal puncture should maximize the effectiveness of the procedure in terms of stone-free status and minimize the risk of complications. CLINICAL CASE: We present the case of a 36-year-old male patient with bilateral lower back pain. A CT urography scan was performed that revealed bilateral lithiasis. The stone on the right side was consistent with an incomplete staghorn stone and a right retrorenal colon was identified. Left flexible nephrolithotripsy and subsequent right percutaneous nephrolithotomy were performed. A puncture was made under fluoroscopic guidance supported by previous digital dissection of all layers of the abdominal wall until gaining access to the retroperitoneum. Colonic lesion was prevented and a tunnel through which the renal unit could be palpated was formed. CONCLUSIONS: The technique of digital insertion and dissection offers safe access to the renal unit that is useful in patients presenting with risk factors for a potential complication. KEYWORDS: Digital; Kidney; Lithiasis; Percutaneous nephrolithotomy.

Percutaneous nephrolithotomy: implementation of digital insertion and dissection as an adjunct to the technique

BACKGROUND: Percutaneous nephrolithotomy (PCNL) was established as a minimally invasive treatment option for kidney stones in the 1970s and is considered a safe and effective procedure, with stone clearance rates of 78-95%. The ideal puncture should maximize the effectiveness of the procedure in terms of stone-free status and minimize the risk of complications. CLINICAL CASE: We present the case of a 36-year-old male patient with bilateral lower back pain. A CT urography scan was performed that revealed bilateral lithiasis. The stone on the right side was consistent with an incomplete staghorn stone and a right retrorenal colon was identified. Left flexible nephrolithotripsy and subsequent right percutaneous nephrolithotomy were performed. A puncture was made under fluoroscopic guidance supported by previous digital dissection of all layers of the abdominal wall until gaining access to the retroperitoneum. Colonic lesion was prevented and a tunnel through which the renal unit could be palpated was formed. CONCLUSIONS: The technique of digital insertion and dissection offers safe access to the renal unit that is useful in patients presenting with risk factors for a potential complication. KEYWORDS: Digital; Kidney; Lithiasis; Percutaneous nephrolithotomy.

Laparoscopic - assisted percutaneous nephrolithotomy as an alternative in the treatment of complex renal calculi in patients with retrorenal colon.

Laparoscopic - assisted percutaneous nephrolithotomy as an alternative in the treatment of complex renal calculi in patients with retrorenal colon.

A prevalence and risk factor analysis in retro-renal colon in china

Objective To investigate the prevalence of retro-renal colon in china and report its potential risk factors. Methods We reviewed the abdominal computed tomography scans (ACTS) that were done in both supine and prone position on the same patient from January 2009 to September 2014.Instances where any part of the colon extended posteriorly to the posterior renal line and extended directly behind the kidney were considered as retro-renal colon. Results We accrued a total of 1 001 patients, including 448 male and 553 female. 63 patients (6.3%) were diagnosed as retro-renal colon. The location of retro-renal colon included 37(3.7%) cases in the left side, 16(1.6%) cases in the right side and 10 (1.0%) cases in bilateral side. Retro-renal colon was found in 14 (1.4%) patients only in supine position, 28 (2.8%) patients only in prone position and 21(2.1%) patients in both supine and prone position. Male patients had higher incidence of retro-renal colon than that in female (8.0% vs. 4.9%). Patients with retro-renal colon were also tend to be older and had smaller body mass index(BMI) value than those patients without retro-renal colon . The multivariate regression demonstrated that smaller BMI value, age and gender were risk factors for the increasing probability of retro-renal colon (all P<0.01). Conclusions Retro-renal colon is more frequently seen in the prone position, especially on the left side. Smaller BMI value, older age, and male gender were risk factors for retro-renal colon. For patients with BMI<18.5 kg/m2 or Age≥69 years, or male patients with left percutaneous access in prone position, pre-operative CT should be done. Key words: Retro-renal colon; Percutaneous renal access; Supine and prone position; Body mass index

Necessity of Preoperative Computed Tomography in Percutaneous Renal Surgery

Aim: Colon injury is an important complication of percutaneous renal surgery. Retrorenal colon on computed tomography (CT) is reported in 10% of patients in the prone position. Our aim is to discuss the necessity of routine preoperative CT and perform a cost analysis of this procedure. Methods: We retrospectively analyzed the records of 285 patients with renal calculi who underwent percutaneous nephrolithotomy between April 2007 and April 2012. After the 2 nd colon perforation, we began to use CT routinely to image stones and to determine the presence of retrorenal colon. We compared the total cost of CTs per incidence of retro colon versus the cost of restoring complications. Results: The first colon injury was extraperitoneal and could be managed conservatively. The cost of this management was only $280. The second colon injury was intraperitoneal and could be managed with a series of open surgeries. The cost of these operations was $8,400. The cost of diagnosis using CT per case of retrorenal colon was $1,833. Conclusion: CT, which should be low-dose, if possible, should be performed routinely in all patients to prevent colon injuries. This technique appears to be cost-effective.

17 The ‘Adana method’ for treating kidney stones with retrorenal colon

17 The ‘Adana method’ for treating kidney stones with retrorenal colon

Colon perforation related to percutaneous nephrolithotomy: from diagnosis to treatment.

We present our experience with the largest series of colon perforation (CP) as complication of percutaneous nephrolithotomy (PNL). From January 1998 to August 2014, 22 cases that presented with PNL-related CP from seven referral centers were retrospectively reviewed. The patients with CP were evaluated in terms of probable risk factors. Peri-operative and postoperative findings, timing of diagnosis, and treatment modalities of the CP were reviewed. Of the 22 patients, previous ipsilateral renal surgery (n:2) and retrorenal colon (n:5) were the risk factors for CP. The CP was directly visualized via nephroscopy during the surgery in 3 (13.6%) and with nephrostography at the end of the procedure in 4 patients (18.2%). In two patients, perforation was realized via the passage of contrast into the colon with nephrostography on the postoperative second day. Postoperative passage of feces through the nephrostomy tube was seen in six patients. The clinical signs in 13 cases directed CP diagnosis. The confirmation of the CP was achieved with a CT scan in all the patients. The patients with extraperitoneal perforation were primarily managed conservatively. Open surgical treatment was performed in cases with intraperitoneal perforation (n:5) and those with extraperitoneal perforation resistant to conservative treatment (n:5). Meticulous evaluation of the risk factors preoperatively is the initial step in the prevention of CP. Timely diagnosis plays essential role in the management of this PNL complication. Although extraperitoneal CP may be managed conservatively, surgery is required for intraperitoneal CPs.

Incidence of retrorenal colon during percutaneous nephrolithotomy.

Objective The aim of this study was to investigate retrorenal colon incidence in percutaneous nephrolithotomy (PNL) interventions made in our clinic.Materials and Methods Clinical data of 804 PNL patients, accumulated over a 7 year period (2006-2012), was surveyed. The patient files were reviewed retrospectively, and only those who had abdominal computed tomography (CT) images before PNL intervention were included in the study. In the CT images, the position of both the ascending and descending colon in relation to the right and left kidneys were evaluated.Results According to our hospital reports, 394 patients with CT images were included in the present study 27 patients (6.9%) had retrorenal colon, of which 18 (4.6%) were on the left side, 4 (1.0%) on the right side and 5 (1.3%) had bilateral retrorenal colons. Colonic perforation complication was seen only in two patients and the colonic perforation rate was 0.3%. These two cases had no CT images.Conclusions PNL, in the process of becoming the standard treatment modality, is a safe and reliable technique for renal stone treatment. Colonic injury should be taken into consideration during PNL interventions of the lower pole of the kidney (especially on the left side) due to the location of retrorenal colon.

Editorial Comment

One of the more contentious issues in the world of percutaneous nephrolithotomy (PNL) during the past few years has been supine vs prone positioning. Each approach has its relative advantages and disadvantages, many of which are enumerated by the authors 1 Proietti S. Sortino G. Antonella G. Single-session supine bilateral percutaneous nephrolithotomy. Urology. 2015; 85: 304-310 Abstract Full Text Full Text PDF PubMed Scopus (21) Google Scholar in the present article. This study 1 Proietti S. Sortino G. Antonella G. Single-session supine bilateral percutaneous nephrolithotomy. Urology. 2015; 85: 304-310 Abstract Full Text Full Text PDF PubMed Scopus (21) Google Scholar will not serve to settle this debate and declare a victor. What it does do, although, is introduce the concept of performing bilateral PNL in the same setting through a supine approach. In the authors' 1 Proietti S. Sortino G. Antonella G. Single-session supine bilateral percutaneous nephrolithotomy. Urology. 2015; 85: 304-310 Abstract Full Text Full Text PDF PubMed Scopus (21) Google Scholar experience, they undertook this procedure in a series of patients and claim excellent results. Although the series is small, the results do objectively suggest a relative safety of this approach. However, the usual caveats to such a series apply as follows: patient selection, surgeon experience, and institutional volume. Nonetheless, for surgeons who do routinely perform supine PNL, the same session bilateral procedure may be considered for select patients. I do not believe that this approach offers meaningful advantages over a similar procedure performed in the prone position but certainly merits consideration for those facile in the supine protocol. Single-session Supine Bilateral Percutaneous NephrolithotomyUrologyVol. 85Issue 2PreviewTo evaluate the effectiveness and safety of supine bilateral percutaneous nephrolithotomy (BPCNL) performed in the same session in patients affected with bilateral renal calculi. Full-Text PDF ReplyUrologyVol. 85Issue 2PreviewIn 1976, Fernstrom and Johansson1 revolutionized the surgical approach to urolithiasis by introducing percutaneous nephrolithotomy (PCNL) in the prone position. That position was considered the only possible way because, at that time, pioneers of endourology estimated that there was a high risk of puncturing the colon. Since then, this surgical approach has continued to evolve to improve the stone-free rate while reducing the invasiveness and morbidity of the procedure. Already in 1990, Valdivia Uria was able to demonstrate that this risk was overestimated, reporting encouraging results of the supine PCNL2 starting from the concept that a retrorenal colon is present only in 1.9% of the cases in the supine position and up to 10% in the prone. Full-Text PDF