Abstract
Minimally invasive options are safe and reliable alternatives for the treatment of nutcracker syndrome (NCS). After continued efforts, our team successfully devised a new and effective therapeutic method: 3D-printed extravascular stenting of the left renal vein. From December 2017 to May 2019, 28 patients (25 men and 3 women) from different parts of China between 18 and 37 years old (mean, 23.6 years) diagnosed with NCS were admitted for laparoscopic 3D-printed extravascular stenting treatment. The post-operative follow-up duration was 6–24 months (median, 16.3 months). Technical success of the operation was achieved in all patients. After treatment, the NCS symptoms all patients resolved or improved during the follow-up period, without relapse. Most symptoms, including macro-/microhematuria, proteinuria, and flank/abdominal pain, tended to resolve within 3–6 months after the surgery; other symptoms, such as left-sided varicocele, also showed varying degrees of improvement at different times post-operatively. Perioperative complications were noted in two patients, including transient and mild lymphatic leakage, without any adverse effects. All extravascular stents were visualized on computed tomography and Doppler ultrasound scans, and no migration or any side effects occurred during the entire follow-up period. Compared to endovascular stenting or polytetrafluoroethylene artificial vessel procedures, 3D-printed polyetheretherketone extravascular stenting has more advantages in terms of stent design and rigidity and approach rationality while successfully preventing stent migration and thrombosis. Therefore, this method may serve as an accurate and effective treatment for NCS patients.
Highlights
Nutcracker syndrome (NCS), known as left renal vein (LRV) entrapment syndrome, is characterized by impeded outflow from the LRV into the inferior vena cava due to an abnormally narrow angle between the abdominal aorta (AA) and the superior mesenteric artery (SMA) or between the AA and the spine (Gulleroglu et al, 2014; de Macedo et al, 2018; Park et al, 2018), resembling a nut between the jaws of a nutcracker
Considering that NCS is mostly due to extrinsic compression of the SMA and preaortic fibrous tissue resulting in LRV entrapment, an appropriate extravascular stent may be effective in relieving LRV stenosis and allowing the recovery of hemodynamics from the outside by supporting the angle between the AA and SMA
CTA showed that the angle between the AA and SMA increased from 21.2 ± 4.5 degrees to 50.3 ± 8.0 degrees and that the anteroposterior diameter ratio of the LRV decreased from 6.5 ± 1.1 to 1.7 ± 0.2
Summary
Nutcracker syndrome (NCS), known as left renal vein (LRV) entrapment syndrome, is characterized by impeded outflow from the LRV into the inferior vena cava due to an abnormally narrow angle between the abdominal aorta (AA) and the superior mesenteric artery (SMA) or between the AA and the spine (Gulleroglu et al, 2014; de Macedo et al, 2018; Park et al, 2018), resembling a nut between the jaws of a nutcracker This phenomenon results in the formation of venous reflux, renal hilar varices, and an increase in LRV pressure, which mainly cause hematuria, proteinuria, and left flank/abdominal pain, as well as pelvic congestion in females and left-sided varicocele in males. Personalized customization of the external stent focuses on fitting to the anatomical characteristics of different individuals to relieve LRV compression while avoiding affecting other important blood vessels and organs
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