Introduction

We present a case highlighting several key aspects of the contemporary management of retroperitoneal fibrosis (RPF) aimed at definitive treatment with minimal morbidity.

Case

A 61-year-old woman was referred to our specialist RPF service following a hospital admission under the vascular team. She had presented with nausea and fatigue and was found to have severely impaired renal function. Her estimated glomerular filtration rate (eGFR) was 9 ml/min off a baseline of 70 ml/min 2 months previously. A noncontrast computerized tomography (CT) showed bilateral hydronephrosis with medialised ureters obstructed by RPF around a 6.2 cm abdominal aortic aneurysm (AAA). She had been initially treated with retrograde insertion of bilateral ureteric stents, following which there was improvement in her clinical condition and in her eGFR to 13 ml/min. She was then discharged to outpatient management.

At review in our RPF clinic 2 weeks later it was noted that her renal function had not really improved following ureteric stent insertion—in fact, the eGFR was lower again at 7 ml/min. The decision was made to insert bilateral nephrostomies and her eGFR improved to a plateau of 38 ml/min.

¹⁸F-fluorodeoxyglucose positron emission tomography (FDG-PET) was also performed. This demonstrated some avidity in the wall of the aneurysm but no significant avidity within the surrounding retroperitoneal soft tissue/RPF (fig. 1). On the basis of this no immunosuppression was prescribed.

Figure 1. ¹⁸F-FDG-PET showing uptake in wall of aneurysm but no significant avidity within the surrounding retroperitoneal soft tissue/RPF.

Two main options for definitive management were discussed with the vascular team and the patient: 1) combined open AAA repair and bilateral ureterolysis, and 2) staged endovascular aneurysm repair (EVAR) followed by robot-assisted laparoscopic bilateral ureterolysis (RALU). The team and the patient chose option 2 as it potentially offered the same result with less morbidity.

EVAR was performed first without complication (fig. 2), and the patient was discharged on postoperative day 1. Two months later, once the outcome from EVAR was deemed satisfactory, the patient underwent a bilateral RALU with omental interposition. The operation took 200 minutes with blood loss of 30 ml. Both nephrostomies were clamped at surgery and removed on postoperative day 1, and the patient discharged.

Figure 2. Fluoroscopy image taken at time of EVAR showing bilateral ureteric stents (green arrows), bilateral nephrostomies (orange arrows), EVAR stent (pink arrow) and arterial catheters (blue arrows).

Both ureteric stents were removed in clinic 3 months later (stents are usually removed 3 weeks postoperatively but had to be deferred due to COVID-19 related restrictions on patient access to hospital). The patient is very well and the eGFR stable 1 year postoperatively at 40 ml/min (ie same as with bilateral nephrostomies).

Discussion

This case highlights 3 key features of the contemporary management of RPF and represents the first reported totally minimally invasive approach to managing such a case requiring ureterolysis and AAA repair.

Ureteric stents are commonly utilized in the setting of ureteric obstruction from RPF. They can provide effective relief from obstruction and are useful as an interim measure whilst waiting for definitive medical or surgical therapy.¹ However, it should be noted that stents do not always provide optimal relief from obstruction, as demonstrated in this case. In our cohort of 433 RPF patients, 39% of those with ureteric obstruction have poorly functioning kidneys and 14% are nephrostomy-dependent. A robust system should be in place to ensure that initial improvement seen following stent insertion continues and is maintained.

Intuitively it would seem that the treatment of primary (idiopathic) RPF and secondary (eg secondary to aneurysm or endovascular graft) should be different. In practice, it is often very difficult to differentiate between the two. For example, all of the following scenarios have been seen in our service: inflammatory RPF secondary to AAA, IgG4 RPF in conjunction with a large AAA, RPF caused by EVAR and inflammatory RPF from AAA cured by EVAR. As a result of the above we apply the same diagnostic principles to every patient with AAA/EVAR and RPF including blood work to look for raised IgG4 levels and other underlying autoimmune conditions, and FDG-PET to assess for activity and decide on medical treatment.²

A mainstay of RPF management is the use of immunosuppression, most commonly in the form of corticosteroid therapy. Despite this, there is little consensus on its efficacy, optimal dose protocols, duration and exact indications. Evidence suggests that the degree of ¹⁸F-FDG-PET avidity can be used to predict a patient’s response to steroid therapy.² In our experience, patients do not benefit from immunosuppression when there is no avidity within the RPF, so side effects can be avoided in this group.

Ureterolysis is a successful way of achieving tube-free ureteric drainage in the context of RPF. Minimal access techniques offer a less morbid alternative to open ureterolysis. Studies comparing open and laparoscopic ureterolysis are limited and retrospective in nature. However, they have demonstrated comparable efficacy with shorter hospital stays and a reduced transfusion requirement with a laparoscopic approach.^3,4

Data on robot-assisted laparoscopic ureterolysis are further limited. Our center’s prospective analysis of 126 robot-assisted laparoscopic cases shows excellent tube-free rates (92% stent free; 100% nephrostomy free) with lower estimated blood loss (40 ml vs 390 ml), shorter postoperative stays (1.5 days vs 7 days) and fewer complications (12% vs 26%) compared to our open series.⁵

The traditional approach to managing such a case would include steroid use and likely combined open aneurysm repair and ureterolysis. Opting for a totally minimally invasive approach with staged EVAR and robot-assisted ureterolysis resulted in a combined hospital stay of 2 postoperative days with minimal blood loss, no morbidity and an excellent outcome for the patient.