Inferior vena cava prosthetic replacement in a patient with horseshoe kidney and metastatic testicular tumor: technical considerations and review of the literature

The International Germ Cell Cancer Collaborative Group (IGCCCG) classifies GCT as a tumor having good, medium, or poor prognosis on the basis of variables including primary tumor site, presence or absence of metastases, levels of AFP (Alpha-FetoProtein), BHCG, and LDH [2]. In view of these variables, the GCT in our patient was classified as carrying a poor prognosis owing to the presence of extrapulmonary lesions and the extremely high level of BHCG (2,250,000 IU/L) at diagnosis. According to the guidelines of the European Association of Urology (March 2011) and the National Comprehension Cancer Network (NCCN 2012), in cases of non-seminomatous GCT treated with orchiectomy and chemotherapy but with residual retroperitoneal lymph nodes >1 cm, removal of the residual mass is warranted and defined as “desperation surgery” in some cases [7, 8]. Of fundamental importance is radical surgery [9], with ad hoc vascular surgery procedures for caval and aortic replacement [4].

Recent studies have shown that about 7% of patients who had received post-chemotherapy retroperitoneal lymph node dissection will require resection of the IVC [10] because of tumoral infiltration into the cava. Recently, Winter et al. evaluated 339 cases with an absolute indication of residual tumor resection after chemotherapy in patients with advanced stage GCT. Surgery of the IVC was necessary in 34 patients (about 10%), in 56% of which vena cava resection and graft placement were required. Resection and interruption of the IVC without reconstruction is possible only in cases of previous caval obstruction and the formation of collaterals which provide for sufficient venous drainage. No complications, e.g., lower limb oedema, decreased renal function, developed in any of the patients undergoing graft reconstruction of the IVC [11]. However, Gloviczki et al. reported a 54% patency rate at 2 years after iliacocaval reconstruction with PTFE grafts [12].

An alternative to grafting may be primary ligation of the IVC without replacement of the removed segment; however, this is associated with a higher post-operative complications rate, a mortality rate of 9%, and severe lower limbs oedema in 36% of cases. Symptoms secondary to chronic venous insufficiency, including secondary varicose veins of the lower limbs, scrotum and abdomen, have been reported in up to 50% of cases. A recent study in 47 patients undergoing caval replacement for infiltrating tumor showed that graft replacement of the IVC prevents venous complications in the extremities and probably contributes to improving quality of life and survival [13].

The IVC can also be replaced with autologous veins, but this option is often impractical because of the difficulty in harvesting enough homologous material to substitute a long venous segment. Spiral vein grafts are not recommended owing to the elevated thrombogenicity of the surface exposed at the suture sites and the high risk of veins collapsing due to the positive intra-abdominal pressure [14]. Currently, PTFE grafts are the prosthesis of choice for caval replacement, with ringed grafts best able to prevent side effects during the immediate post-operative period and symptoms of chronic venous insufficiency [10, 15].

In the case presented here, caval replacement was carried out in the context of a particular anatomic setting: horseshoe kidney. Central fusion of the kidneys occurs when the embryo is 5 to 12 mm, i.e., when the kidneys lie in the true pelvis. Horseshoe kidney is usually located between L3 and L5, lower than normal, because its ascent is impeded by the root of the inferior mesenteric artery. Also, its normal medial rotation is impeded, frequently resulting in an anomalous course of the ureters, which are often ectopic or retrocaval. The kidneys are fused together by a thick isthmus, generally parenchymatous and very often situated anterior to the aorta and the IVC. More rarely it may be found posterior to these vessels or in the interaortocaval space.

The incidence of horseshoe kidney is between 1/400 and 1/800 persons, with a male-to-female ratio of about 2:1. In 90% of cases, the kidneys are fused at the lower poles, either symmetrically (midline fusion) or asymmetrically (L-shaped fusion) [16].

The vascular network of horseshoe kidney varies widely:

Because embryogenesis of the kidney occurs contemporaneously with its venous drainage system in the vena cava, there is a correlation between the presence of horseshoe kidney and venous abnormalities:

The association between non-seminomatous GCT and horseshoe kidney is a rare event and is seen in about 1.3% of patients requiring retroperitoneal lymph node dissection [16]. To our knowledge, no cases have been reported in which replacement of the IVC was also necessary.

As described by Evans et al. [16] and Sogani et al., [19] retroperitoneal lymph node dissection in patients with horseshoe kidney demands scrupulous preparation because of the added complexities arising from the vascular abnormalities associated with this congenital disorder. Added to this is the need to avoid resecting the isthmus as it is often composed of functional renal parenchyma and is therefore richly vascularized. Only the resection of a fibrous isthmus should not lead to a reduction in renal function or to immediate complications such as bleeding.

Scheduled caval replacement will entail careful preoperative imaging to evaluate the morphology and functionality of the isthmus of horseshoe kidney, its arterial vascularization and anatomic relationships with the ureters and venous structures. In young patients, the surgical goal is to achieve radical removal. Winter et al. [11] reported that, on the basis of univariate analysis, the residual mass size (>5 cm) and the IGCCCG prognostic class were predictive factors for completing residual tumor resection in procedures involving the IVC (Inferior Vena Cava), thus providing the basic parameters for surgical planning. Also of fundamental importance is to minimize major hemodynamic complication and preserve renal function. Residual tumor resection with additional vascular procedures is burdened by high mortality, with survival rates of about 71% due to the deteriorated physical condition of patients who have undergone several cycles of chemotherapy [20, 21].

Written informed consent was obtained from the patient for the publication of this case presentation and accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal.