CT and MR Imaging of Complications of Partial Nephrectomy

Pre-gerotal fat patch-A novel alternative to haemostatic agents during partial nephrectomy

Objective

This study aimed to determine if using a pre-gerotal fat patch at open partial nephrectomy (PN) as a haemostatic bolster is a viable alternative to using synthetic haemostatic agents.

Materials and methods

Human Research Ethics Committee approval was obtained for audit of a prospectively kept database from July 2012 to July 2021, which followed outcomes of patients who received a low-tension pre-gerotal fat patch renorrhaphy at open PN. Patient demographics, intraoperative measures, histological outcomes and post-operative complications were analysed. Using a retroperitoneal approach, the peritoneum was mobilised and a vascularised pedicle of pre-gerotal fat was rotated in the direction of the kidney. Routine definition of the hilum, clamping of the hilar vessels and dissection of mass followed. After watertight closure and haemostasis, the harvested pre-gerotal fat patch was placed over the defect and secured using low-tension renorrhaphy. Two-layer closure of the abdominal wall with placement of a drain was routine.

Results

A total of 55 patients underwent open PN. Mean age was 60.4 (35-77) years. There were 38 men and 17 women, and 32 right and 23 left PNs. Mean mass size was 31.9 mm (10-95 mm) and collecting system was breached in 36.5% of cases. One patient (1.9%) suffered a Clavien-Dindo IIIb complication requiring return to theatre and transfusion due to a bleed from an intercostal artery. There were no renal bed bleeds, urine leaks or urine fistulas detected. Mean intraoperative blood loss was 355 mL (50-1500 mL) and mean post-operative creatinine increased by 10.7 μmol/L (51-172 μmol/L). Mean follow up was 40.2 (4-109) months.

Conclusion

Utilisation of an anatomical pre-gerotal fat patch to provide pressure at the renorrhaphy site during open PN is an effective technique to assist with surgical haemostasis. This simple technique avoids the costs of haemostatic agents, whilst adding minimal operating time to procedures.

Complications after Nephron-sparing Interventions for Renal Tumors: Imaging Findings and Management

The two primary nephron-sparing interventions for treating renal masses such as renal cell carcinoma are surgical partial nephrectomy (PN) and image-guided percutaneous thermal ablation. Nephron-sparing surgery, such as PN, has been the standard of care for treating many localized renal masses. Although uncommon, complications resulting from PN can range from asymptomatic and mild to symptomatic and life-threatening. These complications include vascular injuries such as hematoma, pseudoaneurysm, arteriovenous fistula, and/or renal ischemia; injury to the collecting system causing urinary leak; infection; and tumor recurrence. The incidence of complications after any nephron-sparing surgery depends on many factors, such as the proximity of the tumor to blood vessels or the collecting system, the skill or experience of the surgeon, and patient-specific factors. More recently, image-guided percutaneous renal ablation has emerged as a safe and effective treatment option for small renal tumors, with comparable oncologic outcomes to those of PN and a low incidence of major complications. Radiologists must be familiar with the imaging findings encountered after these surgical and image-guided procedures, especially those indicative of complications. The authors review cross-sectional imaging characteristics of complications after PN and image-guided thermal ablation of kidney tumors and highlight the respective management strategies, ranging from clinical observation to interventions such as angioembolization or repeat surgery. Work of the U.S. Government published under an exclusive license with the RSNA. Online supplemental material and the slide presentation from the RSNA Annual Meeting are available for this article. Quiz questions for this article are available in the Online Learning Center. See the invited commentary by Chung and Raman in this issue.

Diagnostics and prognostic evaluation in renal cell tumors: the German S3 guidelines recommendations

The German guidelines on renal cell carcinoma (RCC) have been developed at highest level of evidence based on systematic literature review. In this paper, we are presenting the current recommendations on diagnostics including preoperative imaging and imaging for stage evaluation as well as histopathological classification. The role of tumor biopsy is further discussed. In addition, different prognostic scores and the status of biomarkers in RCC are critically evaluated.

Narrative review of vascular iatrogenic trauma and endovascular treatment

Iatrogenic injury is unfortunately a leading cause of morbidity and mortality for patients worldwide. The etiology of iatrogenic injury is broad, and can be seen with both diagnostic and therapeutic interventions. While steps can be taken to reduce the occurrence of iatrogenic injury, it is often not completely avoidable. Once iatrogenic injury has occurred, prompt recognition and appropriate management can help reduce further harm. The objective of this narrative review it to help reader better understand the risk factors associated with, and treatment options for a broad range of potential iatrogenic injuries by presenting a series of iatrogenic injury cases. This review also discusses rates, risk factors, as well as imaging and clinical signs of iatrogenic injury with an emphasis on endovascular and minimally invasive treatments. While iatrogenic vascular injury once required surgical intervention, now minimally invasive endovascular treatment is a potential option for certain patients. Further research is needed to help identify patients that are at the highest risk for iatrogenic injury, allowing patients and providers to reconsider or avoid interventions where the risk of iatrogenic injury may outweigh the benefit. Further research is also needed to better define outcomes for patients with iatrogenic vascular injury treated with minimally invasive endovascular techniques verses conservative management or surgical intervention.

"Renal emergencies: a comprehensive pictorial review with MR imaging"

Superior soft-tissue contrast and high sensitivity of magnetic resonance imaging (MRI) for detecting and characterizing disease may provide an expanded role in acute abdominal and pelvic imaging. Although MRI has traditionally not been exploited in acute care settings, commonly used in biliary obstruction and during pregnancy, there are several conditions in which MRI can go above and beyond other modalities in diagnosis, characterization, and providing functional and prognostic information. In this manuscript, we highlight how MRI can help in further assessment and characterization of acute renal emergencies. Currently, renal emergencies are predominantly evaluated with ultrasound (US) or computed tomography (CT) scanning. US may be limited by various patient factors and technologist experience while CT imaging with intravenous contrast administration can further compromise renal function. With the advent of rapid, robust non-contrast MRI, and magnetic resonance angiography (MRA) imaging studies with short scan times, free-breathing techniques, and lack of ionization radiation, the utility of MRI for renal evaluation might be superior to CT not only in diagnosing an emergent renal process but also by providing functional and prognostic information. This review outlines the clinical manifestations and the key imaging findings for acute renal processes including acute renal infarction, hemorrhage, and renal obstruction, among other entities, to highlight the added value of MRI in evaluating the finer nuances in acute renal emergencies.

Imaging of Abdominal Postoperative Complications

We present a case-based review of abdominal postoperative complications, organized by organ system affected, including wound/superficial, hepatobiliary, pancreatic, gastrointestinal, genitourinary, and vascular complications. Both general complications and specific considerations for certain types of operations are described, as well as potential pitfalls that can be confused with complications. Representative cases are shown using all relevant imaging modalities, including CT, fluoroscopy, ultrasound, MRI, and nuclear medicine. Management options are also described, highlighting those that require radiologist input or intervention.

Magnetic resonance imaging characteristics and changes in hemostatic agents after partial nephrectomy

PURPOSE

To evaluate the characteristics of images generated by magnetic resonance imaging (MRI) and changes in the mass-like lesion (MLL) during the follow-up of patients who underwent partial nephrectomy (PN) with the intra-operative use of hemostatic agents (HAs).

METHODS

The records of patients who had undergone PN in our clinic due to renal mass between January 2013 and August 2018 were retrospectively reviewed. Our study included 47 patients who were administered one or more HAs during the PN and who received diffusion and dynamic MRI at the post-operative 2nd/4th Queryand 12th month.

RESULTS

MLL is defined as T2 heterogeneous, intermediate-signal intensity bolster-related mass with a pseudocapsule in the renal parenchymal defect. When we looked at the morphological changes of MLL, the mean largest axial dimensions of masses were 27.3 (range 12.2-44.7) mm in the first follow-up period (2nd/4th months) and 21.2 (range 11-44.7) mm in the 12th month follow-up period. The average change in size of MLL was - 0.66 mm/month. We did not see any significant relationship between observation of MLL in the post-operative follow-up MRI images and the use of HAs such as Surgicel^®, Spongostan^®, and autologous fatty tissue as well as the amount of the agents used in PN operations (p = 0.405, p = 0.159, respectively).

CONCLUSIONS

The distinction of MLL causing bolster-related mass and granulomatosis tissue from relapse/recurrence can be made based on the change in mass size observed in the MR images and image characteristics.

Findings and Impact of Early Imaging After Partial Nephrectomy

INTRODUCTION

American Urological Association guidelines for surveillance of renal-cell carcinoma after partial nephrectomy recommend imaging within 3-12 months of surgery. Imaging following partial nephrectomy may be difficult to interpret due to the surgical defect, the use of surgical material, and normal postoperative fluid collections. Our primary objective was to evaluate the frequency of indeterminate postoperative imaging results and how those radiographic findings altered patient management.

METHODS

Retrospective chart review from 2006 to 2013 of patients who had undergone open, laparoscopic, and robotic partial nephrectomy at our institution was completed. There was a minimum of 2 years of follow-up imaging. Radiology reports were reviewed from follow-up imaging and were categorized as "normal" or "abnormal."

RESULTS

We identified 180 patients with 127 (70.5%) considered to have normal findings on initial follow-up imaging, and 53 (29.5%) with abnormal findings. Median time to initial postoperative imaging for normal findings was 6.8 months compared with 4.4 months for patients with abnormal postoperative scans (p = 0.02). On subsequent imaging, 60% of abnormal studies were downgraded to normal. The median time to receive a second postoperative image from surgery in the normal and abnormal groups was 13.2 and 10.2 months, respectively. The median time interval to the second imaging study was 6.3 months for normal initial scans compared with 5.2 months for initially abnormal scans (p ≤ 0.01).

CONCLUSIONS

Early postoperative imaging after partial nephrectomy frequently results in "abnormal" findings and more subsequent radiology exams even though the findings rarely represent cancer recurrences. Based on our results, and pending further validation from other centers, we believe postoperative CT or MRI surveillance after partial nephrectomy can be safely deferred until 1 year after surgery.

Computed Tomography Imaging Features and Changes in Hemostatic Agents After Laparoscopic Partial Nephrectomy

PURPOSE

Urologists and radiologists should be aware of the CT scan appearance of laparoscopic partial nephrectomy (LPN) with the various hemostatic agents since they may confound the interpretation of these radiographic findings. We report the various postoperative CT scan appearance and changes after LPN.

MATERIALS AND METHODS

We reviewed CT scans retrospectively (within 3 months) of 86 patients who underwent LPN using various hemostatic agents between March 2008 and July 2014. We analyzed the CT findings after LPN, including postoperative changes, tumor recurrence, and complications. We also discuss changes in abnormal features, such as mass-like lesions and gas formation, on follow-up CT scans.

RESULTS

To categorize the postoperative changes, we classified them according to their specific CT findings: (1) a combination of perinephric stranding and postsurgical fluid collection (n = 46), (2) mass-like lesions (n = 35), (3) a parenchymal defect (n = 2), (4) local recurrence at the surgical site (n = 1), (5) a large hematoma as a complication after LPN (n = 2), (6) gas pockets, which may be a response to postsurgical fluid collection around soft tissue (n = 35), (7) fat at the excision site (n = 2; Fig. 7 ), and (8) contrast extravasation in the delayed phase (n = 1). Mass-like lesions were visible in 35 cases. The average change in size of bolster masses was -1.19 mm/month. However, the overall change in enhancement of mass-like lesions was not significant over time. Foci of gas were noted in 16 patients at the resection site in the first follow-up period (<3 months), as late as 40 days after the procedure.

CONCLUSIONS

Knowledge of CT imaging features and changes in hemostatic agents following LPN is important in interpreting postoperative CT scans, as postoperative changes can be confused with tumor recurrence and can mimic abscesses.

Multidetector CT imaging of complications after laparoscopic nephron-sparing surgery

Purpose

Laparoscopic nephron-sparing surgery (L-NSS) is increasingly performed to treat localised renal lesions. However, the associated morbidity is non-negligible, with a rate of major complications approaching 10 %.

Methods and Results

This paper provides an overview of indications, surgical techniques and results of L-NSS; explains the incidence, risk factors and manifestations of postoperative complications; discusses the preferred multidetector computed tomography (CT) acquisition techniques; illustrates the appearance of normal postoperative images following L-NSS; and reviews, with example images, the most common and unusual iatrogenic complications. These include haematuria, haemorrhage, vascular injuries, infections and urinary leaks. Most emphasis is placed on CT, which provides rapid, reliable triage and follow-up of iatrogenic complications after L-NSS, identifying occurrences that require transarterial embolisation or repeated surgery.

Conclusions

Multidetector CT allows precise assessment of the surgical resection site; detection of pneumoperitoneum and subcutaneous emphysema; quantification of retroperitoneal blood; and identification of active bleeding, pseudoaneurysms, arterio-venous fistulas, abscess collections and extravasated urine.

Teaching Points

• Laparoscopic nephron-sparing surgery (NSS) is increasingly performed to treat renal lesions.

• Radiologists are increasingly requested to investigate suspected post-surgical NSS complications.

• Post-NSS complications include haemorrhage, haematuria, vascular injuries, infections and urinary leaks.

• Multidetector CT allows choice between conservative treatment, transarterial embolisation or surgery.

Computed tomography after nephron-sparing surgery

The increased use of abdominal cross-sectional imaging has contributed to a greater detection of incidental small renal masses. Treatment options for localized disease renal cell carcinoma include radical nephrectomy or partial nephrectomy (PN), the former being preferred for treatment of early-stage tumors. The most adopted technique for follow-up imaging is contrast-enhanced computed tomography (CT), whose findings can cause uncertainty and unnecessary repetition of examinations. Our purpose is to describe CT findings after PN and to describe evolution in time of such images.

Complications of minimally invasive procedures of the abdomen and pelvis: a comprehensive update on the clinical and imaging features

Minimally invasive gastrointestinal, genitourinary, and gynecological procedures are widely used in the clinical practice for diagnostic and therapeutic purposes. Complications both minor and major are not uncommon with these procedures. Imaging plays an important role in the detection and optimal management of these complications. Familiarity with the clinical and imaging features of these complications by radiologists can help in their timely detection.

CT appearances following laparoscopic partial nephrectomy for renal cell carcinoma using a rolled cellulose bolster

Abstract Purpose: To describe the evolving computed tomography (CT) appearances of a cellulose surgical bolster used as a hemostatic agent in patients who undergo laparoscopic partial nephrectomy for renal cell carcinoma. Materials and methods: We retrospectively reviewed the follow-up CT studies of 33 patients with stage T1N0M0 renal carcinoma who underwent laparoscopic partial nephrectomy using a rolled, oxidized, regenerated cellulose sheet sutured in place as a bolster in the parenchymal defect. Thirteen patients undergoing laparoscopic partial nephrectomy without the use of a bolster were also evaluated to differentiate imaging features. Results: The bolster-related masses were significantly larger than those seen in the non-bolster patients. There was a decrease in size of the post-operative bolster-related mass with time. The bolster shape evolved with time, initially appearing oval, and becoming irregular with decreasing size. Equivocal increase in attenuation of 10–20 HU was seen in 6 patients. Increase in attenuation of greater than 20 HU was seen in 3 patients. There was no evidence of tumor recurrence in any of the patients. Invagination of fat was seen in two bolster-related masses at 18 months or greater. Conclusions: Cellulose bolster has a variable appearance on follow-up CT exams. Evolutionary features include reduction in bolster size and shape with time leading finally to non-visualization. Bolster enhancement can mimic abscesses and tumor recurrence.

Radiologic evaluation of small renal masses (II): posttreatment management

The increase in the detection of small renal masses (SRMs) and their best knowledge leads to a change in the therapeutic management of these lesions. The use of a less aggressive surgical technique or even an expectant attitude is the current tendency, in order to preserve as much renal function as possible. Imaging techniques are essential in the followup of these lesions. It allows us to know the postsurgical changes and possible complications due to treatment and the presence of local recurrence and metastases. Furthermore, a close radiological followup of SRM related to ablative treatments is mandatory. The purpose of this article is to reveal the imaging features of complications due to surgical or ablative treatments, local recurrence and metastasis, as well as their followup.

CT Appearance of Absorbable Suture Clips Following Nephron Sparing Surgery

Absorbable suture clips used during partial nephrectomy may be recognized as small hyperdensities near the excision site at 5 months after implantation. They may be completely resorbed and no longer visible at 11 months after implantation.