Imaging evaluation of renal trauma

The Japanese Urological Association's clinical practice guidelines for urotrauma 2023

The Japanese Urological Association's guidelines for the treatment of renal trauma were published in 2016. In conjunction with its revision, herein, we present the new guidelines for overall urotrauma. Its purpose is to provide standard diagnostic and treatment recommendations for urotrauma, including iatrogenic trauma, to preserve organ function and minimize complications and fatality. The guidelines committee comprised urologists with experience in urotrauma care, selected by the Trauma and Emergency Medicine Subcommittee of the Specialty Area Committee of the Japanese Urological Association, and specialists recommended by the Japanese Association for the Surgery of Trauma and the Japanese Society of Interventional Radiology. The guidelines committee established the domains of renal and ureteral, bladder, urethral, and genital trauma, and determined the lead person for each domain. A total of 30 clinical questions (CQs) were established for all domains; 15 for renal and ureteral trauma and five each for the other domains. An extensive literature search was conducted for studies published between January 1, 1983 and July 16, 2020, based on the preset keywords for each CQ. Since only few randomized controlled trials or meta-analyses were found on urotrauma clinical practice, conducting a systematic review and summarizing the evidence proved challenging; hence, the grade of recommendation was determined according to the 2007 "Minds Handbook for Clinical Practice Guidelines" based on a consensus reached by the guidelines committee. We hope that these guidelines will be useful for clinicians in their daily practice, especially those involved in urotrauma care.

Renal trauma

Urinary tract injury occurs in 10% of all abdominal trauma patients, and the kidney is the most commonly injured organ in the urinary tract. CT with contrast enhancement is the modality of choice for cross-sectional imaging of renal trauma because it quickly and accurately can demonstrate injury to the renal parenchyma, renal pedicles, and associated abdominal or retroperitoneal organs. This article reviews the mechanism, clinical features, imaging modalities, and CT imaging findings according to the classification of the renal trauma. Trauma to underlying abnormal kidneys, iatrogenic renal injuries, and complications of renal trauma are reviewed also.

Renal Injury: 5-Year Experience and Literature Review

INTRODUCTION

Appropriate management of renal trauma is controversial. The purpose of this study is to present our 5-year experience in renal trauma and review the literature.

MATERIALS AND METHODS

From 1999 to 2003, 28 patients were identified with renal injuries. 25 (89.3%) of the injuries were caused by blunt trauma, 2 (7.1%) by stab wounds, and 1 (3.6%) by gunshot wound. Methods for diagnosis included ultrasonography (US), computed tomography (CT), diagnostic peritoneal lavage (DPL), combinations of more than one technique or no one of them. The English-language literature about renal trauma was also identified using Medline, and additional cited works not detected in the initial search obtained.

RESULTS

18 patients underwent immediate or during 24 h operation; while 5 nephrectomies were performed. 11 patients with grade I to III injuries were selected for nonoperative management of renal injuries. All complications were noted and studied according to the initial therapeutic management and grade. Follow-up was clinical and radiological. 3 postoperative deaths were observed.

CONCLUSION

The goals of treatment of renal injuries include accurate staging and minimal complications. Surgery can be avoided in most cases of blunt renal injury but there is also a trend towards conservative management of penetrating trauma. Nephrectomy is associated with high-grade renal injuries, while minor renal injuries can safely be managed conservatively.

Complications of Renal Trauma

Renal trauma is rare, and significant complications from renal trauma are generally rarer still occurring in less than 5% in modern series. Close follow-up of injured patients and scrupulous use of imaging, including computed tomography scan, arteriogram, or retro-grade pyelogram when appropriate, increase detection rates and establish the diagnosis in most patients. Treatment varies by etiology and may range from watchful waiting to percutaneous drainage to, in rare cases, nephrectomy.

Validity of Computerized Tomography in Blunt Renal Trauma

PURPOSE

Improved imaging techniques and new therapeutic possibilities require rethinking the indication for laparotomy with regard to blunt renal trauma. Refined classification systems would facilitate the decision relating to therapy but they are based on knowledge of the imaging accuracy of computerized tomography (CT). We evaluated the validity of the CT depiction of renal injuries.

MATERIALS AND METHODS

A total of 42 porcine kidneys were subjected to traumatization of various degrees. They then underwent CT examination and were subsequently cross-dissected into slices 3 mm thick. The comparative evaluation involved 2,080 CT images and 1,819 macroscopic sectional views, which showed 3,521 and 3,778 individual lesions, respectively.

RESULTS

Using CT the overall extent of injury in renal trauma was only slightly overrated at an average of 15% higher than that seen on macroscopy. Simple linear lesions tended to be over assessed and parenchymal destruction tended to be under assessed. Central lesions were depicted more frequently than peripheral lesions. CT of medullary lesions and parenchymal detachment was not feasible.

CONCLUSIONS

CT of the kidney enables the distinction of different kinds of lesions and their localization well. Pelvic structures or vessels can imitate linear lesions. However, this imaging procedure can be used as a basis for refining categorization systems for blunt renal trauma. It can also be used to obtain a large quantity of lesion data for biomechanical investigations.

Advances in uroradiological imaging

The development of new imaging techniques and the refinement of established methods in uroradiological imaging is proceeding rapidly. In the last few years several important developments have been implemented in the routine diagnostic evaluation of urological patients.A milestone is the recent advent of multidetector helical computed tomography (CT), enabling the radiologist to provide the clinician with high-quality three-dimensional (3-D) reconstructions of the urological organs. Powerful workstations are an indispensable tool in the post-processing of CT and magnetic resonance imaging (MRI)data. Significant advances in imaging were obtained in the fields of oncological imaging (e.g. prostate MRI and spectroscopic imaging), paediatric uroradiology(e.g. MR urography) and the evaluation of stone disease by unenhanced helical CT.