Reoperative robotic laparoscopic extracorporeal stent implantation following the failure of endovascular stent implantation for nutcracker syndrome

Abstract

Nutcracker syndrome, which arises from the compression of the left renal vein, lacks definitive treatment protocols. When conservative measures fail, options encompass open surgery, endovascular intervention, laparoscopic surgery, and robotic laparoscopic surgery. We documented the case of a young individual diagnosed with nutcracker syndrome who underwent endovascular stent implantation. However, this intervention resulted in stent displacement and failed to alleviate symptoms or address the stenosis. Consequently, the patient underwent robotic laparoscopic extracorporeal stent placement. On the second day postoperation, the patient developed a retroperitoneal hematoma (measuring 80 mL) subsequent to physical activity. The hematoma was managed through blood transfusion and enforced bed rest. At the 3-month follow-up, symptoms had completely resolved. The patient consented for publication of the video and case report.

The patient is a 41-year-old male who presented to our hospital with the primary complaint of left-sided lower back pain accompanied by hematuria for over 2 years. Two years prior to admission, the patient experienced a dull ache in the left lumbar region without any discernible trigger, which exacerbated following physical exertion and was accompanied by gross hematuria and foamy urine. The patient underwent treatment in the outpatient department, where an ultrasonographic and magnetic resonance imaging evaluation of the urinary system was conducted. The assessment revealed compression of the left renal vein at the intersection with the abdominal aorta, with the most constricted segment measuring 2 mm in diameter. Following this, a stent was inserted into the left renal vein within the outpatient department. Postprocedure, the patient adhered to a regimen of regular anticoagulant therapy, specifically with rivaroxaban. After the treatment, the symptoms of low back pain and hematuria still occurred intermittently, and the symptoms gradually aggravated 1 year after the operation. He was admitted to the urology department of our hospital on December 27, 2024.

The patient had no history of diagnosed illnesses. The patient denied any history of smoking, alcohol consumption, and familial medical history. Upon physical examination, the patient’s consciousness was observed to be normal. The patient’s temperature was recorded at 36.4°C, pulse rate at 59 beats per minute, respiratory rate at 17 breaths per minute, and blood pressure at 123/78 mmHg. Examination of the cardiopulmonary and abdominal regions revealed no abnormalities. No enlargement of the kidneys or palpable masses was detected in either renal area; however, tenderness and pain upon percussion were noted. No abnormal vascular murmurs were auscultated. Additionally, no abnormalities were identified in the bilateral ureters, bladder region, or external genitalia.

Treatment process

Upon admission, the patient underwent a series of comprehensive examinations and diagnostic tests. The urinalysis indicated the presence of occult blood at a level of 3+, and a microscopic examination of the urine sediment revealed an elevated count of red blood cells, white blood cells, and bacteria; all other tests yielded normal results (Fig 1). The preoperative ultrasound confirmed that the peak velocity was 100 cm/s. The computed tomography (CT) imaging of the lower abdomen and pelvis (Fig 2, A) disclosed postoperative alterations subsequent to the placement of a stent in the left renal vein. The stent was not optimally positioned at the location of the most severe renal vein stenosis, resulting in an incomplete alleviation of the constriction. With the diagnosis of nutcracker syndrome (NCS) confirmed, a robotic laparoscopic procedure for the placement of an external stent and renal vein decompression was conducted on December 31, 2024, under general anesthesia. Intraoperative observations indicated that the stent within the renal vein had significantly expanded, exhibiting thin walls with portions of the stent protruding through the vessel wall (Fig 3).The surgical site of the left renal vein was meticulously mobilized to reveal the abdominal aorta and superior mesenteric artery. A 1-cm diameter Bade artificial blood vessel (polytetrafluoroethylene [PTFE] annular stent) was fashioned into a ring-shaped stent by means of a C-shaped incision to provide support for the constricted renal vein. The stent was securely affixed with nonabsorbable sutures to the adjacent tissues to avert any displacement (Fig 4). The surgical procedure was uneventful.To ensure complete drainage of blood, lymph, and other bodily fluids, and to prevent postoperative infection and fever, the patient was transferred back to the ward subsequent to the abdominal drainage procedure and instructed to remain strictly confined to bed. The postoperative follow-up ultrasound showed that the peak velocity of the renal vein decreased to 60 cm/s, indicating that the surgical procedure effectively relieved the compression of renal vein stenosis. On the second postoperative day (January 2, 2025), an increase in drainage volume was observed following the patient’s self-initiated activity, and a blood routine recheck indicated a progressive decline in red blood cell count and hemoglobin levels (Figs 5 and 6). There was a significant suspicion of internal bleeding. On January 3, 2025, a subsequent CT scan of the upper abdomen, lower abdomen, and pelvis (Fig 7, A) revealed slightly high-density shadows in the left abdomen and pelvis, suggesting the presence of a hematoma. It is recommended to conduct laparoscopic exploration; however, the patient’s vital signs were stable, and there was no indication for urgent surgical intervention. After thoroughly apprising the patient of the operation’s necessity and associated risks, the patient declined the laparoscopic exploration. The patient was directed to maintain a strict supine position, and to receive frozen plasma and red blood cell transfusions to rectify anemia and restore blood volume. A recheck of hemoglobin levels indicated a substantial increase from preoperative levels, and the patient reported no discomfort. A follow-up CT scan of the lower abdomen and pelvis on day 9 (Fig 7, B) confirmed the placement of the left renal vein stent, abdominal aorta-superior mesenteric artery artificial vascular placement, and postrenal vein release surgery. The hematoma in the lower left abdomen and pelvis had diminished compared with previous scans, hemoglobin levels were stable, there was no indication of recurrent bleeding, and the wound had healed satisfactorily. A follow-up outpatient visit was conducted 3 months postdischarge. The patient reported no further discomfort, and routine blood and urine tests had normalized. The CT scan indicated complete absorption of the hematoma (Fig 8).

Fig 1.

Changes in routine urine of patients. BACT, Bacteria; RBC, red blood cells; WBC, white blood cells.

Fig 2.

Preoperative and postoperative plain computed tomography (CT) results. A, Preoperative internal stent condition. B, Postoperative external stent implantation.

Fig 3.

Internal stent intraoperative positioning diagram.

Fig 4.

Completion of external stent placement. LRA, Left renal artery; LRV, left renal vein; SMR, superior mesenteric vein.

Fig 5.

Trend of hemoglobin changes in patient.

Fig 6.

Trend chart of red blood cell (RBC) changes in patient.

Fig 7.

Hematoma status during hospitalization. A, Hematoma status on January 3, 2025. B, Hematoma status on January 9, 2025.

Fig 8.

Computed tomography (CT) review at 3 months after discharge (hematoma completely absorbed).

This article pertains to a patient who has been thoroughly informed and has provided consent by signing an informed consent form. The publication of this article has been approved by the Ethics Committee of Tianjin Third Central Hospital. (Approval No.: [IRB2018-030-01]). Written informed consent was obtained from the patient.

Discussion

NCS is a vascular anatomical disorder characterized by the compression of the left renal vein at the angle formed by the abdominal aorta and the superior mesenteric artery, which impedes venous return.¹ The “Nutcracker Phenomenon” was initially described by El-Sadr and Mina in 1950.² However, it was not until 1972 that the Belgian physician De Schepper correlated this anatomical phenomenon with clinical symptoms, thereby coining the term “nutcracker syndrome.”³ Subsequently, NCS has garnered increasing attention, with research into its etiology, clinical manifestations, diagnosis, and treatment expanding and becoming more comprehensive, resulting in a progressive increase in diagnostic rates. The classical clinical manifestations encompass left flank and abdominal pain, gross or microscopic hematuria, and proteinuria. Some individuals may also experience varicocele or pelvic congestion syndrome (in females).⁴ Epidemiological studies indicate that NCS is more prevalent among tall adolescents and young adults, with a marginally higher prevalence in females compared with males.⁵ Long-term untreated NCS can result in renal vein hypertension, progressive renal function deterioration, and potentially irreversible damage such as glomerulosclerosis.

Contemporary therapeutic approaches are principally categorized into conservative therapy and invasive interventions. For individuals presenting with less severe symptoms or in the initial phases of the disease, it is advised to implement high-protein dietary regimens and weight gain as conservative strategies to augment the thickness of the retroperitoneal fat pad, thereby mitigating vascular compression. Nevertheless, the efficacy rate is observed to be below 30%.⁶ Surgical interventions encompass the placement of endovascular stents and the execution of either open or laparoscopic extracorporeal stent placement. Endovascular stent placement presents benefits such as less invasive procedures and swifter recuperation, yet it is accompanied by risks including stent migration (with an incidence rate of approximately 10% to 15%), intrastent thrombosis (5% to 8%), and the long-term risk of restenosis, which may result in symptom recurrence due to inadequate stent rigidity.⁷ In contrast, extracorporeal stenting entails the implantation of artificial or synthetic materials around the left renal vein to offer external support, providing more enduring anatomical correction.

In addition to the implantation of vascular and extracorporeal stents, open surgical procedures continue to be the method of choice for complex scenarios, encompassing renal vein transposition, renal vein bypass grafting, vaginal vein transposition, and aortic decompression. Renal vein transposition,⁸ the most frequently utilized open surgical technique, involves the advancement of the left renal vein anteriorly into the inferior vena cava. This method effectively mitigates compression issues by repositioning the left renal vein anterior to the aorta. The renal vein bypass grafting technique⁹ utilizes either autologous or artificial vessels, such as the great saphenous vein or polytetrafluoroethylene, to circumvent the compressed segment. This procedure is particularly appropriate for instances characterized by severe fibrosis of the left renal vein or anatomical configurations that preclude transposition. When the left vaginal vein possesses a sufficient diameter for anastomosis, its relocation can function as a preliminary therapeutic option.¹⁰ This minimally invasive alternative yields satisfactory outcomes without the need for foreign body implantation, effectively alleviating pelvic congestion in female patients. Furthermore, aortic decompression, achieved through aortic release or the enlargement of the aortic window to reduce pressure on the left renal vein, represents a relatively uncommon surgical intervention in clinical practice. The patient elected to undergo robotic-assisted extracorporeal stent implantation rather than open surgical procedures, such as renal vein transposition, because the computed tomography scans indicated severe perivascular calcification that would have introduced substantial risks associated with venous displacement. The utilization of PTFE grafts to externally bolster the compressed left renal vein circumvented the risks inherent to vascular grafting and alleviated the compression issues. Additionally, the robot’s three-dimensional magnification feature facilitated precise anatomical delineation of the left renal vein-aortic interface, permitting graft fixation without tension and markedly diminishing anastomotic stress.¹¹

Postoperative management should concentrate on the standardization of anticoagulation therapy, particularly for patients with intravascular stents, the dynamic monitoring of renal function, and the early detection of symptom recurrence. It is advised to conduct a reevaluation of urine routine, renal vein ultrasound, and renal function every 3 months within the first year postsurgery. Additionally, it is imperative to avoid strenuous physical activity or excessive bending to prevent stent displacement.¹² For women in their reproductive years, it is crucial to remain vigilant regarding the potential increase in intra-abdominal pressure during pregnancy, which could exacerbate the condition.

The patient presented in this case is a 41-year-old male who has exhibited symptoms consistent with NCS for a duration of 2 years. The recurrence of symptoms 1 year subsequent to the initial implantation of an endovascular stent in the left renal vein was confirmed by imaging to be due to the displacement of the proximal stent, resulting in the reocclusion of the left renal vein. This outcome underscores the limitations of endovascular intervention in scenarios characterized by significant anatomical variations. The subsequent surgical intervention involved the utilization of a robot-assisted laparoscopic approach for the extracorporeal placement of a stent, capitalizing on the high-resolution three-dimensional visualization and the seven degrees of freedom afforded by the robotic arm of the da Vinci system to conduct an accurate anatomical dissection of the left renal vein and the secure fixation of the PTFE artificial vessel stent. Intraoperative blood loss was restricted to 50 mL, and the operative duration was abbreviated to 120 minutes, thereby evidencing the substantial benefits conferred by robotic technology in the execution of intricate retroperitoneal procedures.

It is noteworthy that, subsequent to the second day postsurgery, the patient experienced acute abdominal discomfort upon independently rising from bed. A CT scan identified a retroperitoneal hematoma, estimated at approximately 80 mL, which was presumably attributable to minor hemorrhaging at the anastomotic site. Through conservative management, which included absolute bed rest, administration of hemostatic agents, and blood transfusions, the hematoma was observed to have gradually resolved, thereby obviating the necessity for a secondary surgical intervention. This incident serves as a poignant reminder that, despite the minimally invasive reputation of robotic surgery, premature vigorous activity in the immediate postoperative phase can potentially elevate tension at the vascular anastomosis, particularly within the timeframe of anticoagulation therapy, necessitating stringent limitations on patient activity levels. At the 3-month follow-up, complete resolution of hematuria and proteinuria was observed, with normalization of blood parameters and renal function indices, and stabilization of the artificial vessel’s position as evidenced by enhanced CT, confirming the complete alleviation of the left renal vein. These outcomes are in alignment with the follow-up data over a 60-month period post-Supera stent implantation, thus corroborating the enduring efficacy of stent therapy.

This case provides important insights for NCS treatment: First, in cases where endovascular stent implantation fails, more thorough external stenting should be actively considered. Robotic laparoscopic technology can significantly enhance surgical precision and safety, especially suitable for younger patients with higher demands for aesthetics and rapid recovery. Second, postoperative bleeding risk must be reduced through comprehensive preventive measures: using biological protein glue to close the wound during surgery, implementing delayed anticoagulation strategies within 24 hours postoperatively, and formulating a detailed step-by-step activity plan, starting with bed rest at 6 hours postoperatively, gradually transitioning to standing beside the bed at 24 hours, and finally achieving indoor walking within 72 hours.

Conclusions

Patients afflicted with NCS who have not responded to endovascular stenting may find robotic laparoscopic stent placement to be an efficacious therapeutic alternative capable of precisely alleviating the compression of the left renal vein. Postsurgical care should emphasize the prevention and management of hemorrhagic risks, coupled with stringent restrictions on initial mobilization and the formulation of a tiered exercise regimen.

Funding

None.

Disclosures

None.

Appendix (online only)

Supplementary Video (online only)

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