TCAS 04. Application of extravascular stenting for Nutcracker Syndrome: a clinical experience
Nutcracker Syndrome, clinically carectered by hematuria, flank pain, left-sided varicocele or pelvic congestion, refers to the compression of the left renal vein between the superior mesenteric artery and the abdominal aorta. Though its incidence is quite prevalent through observing distended left renal vein on ultrasonography and CT, asymtomatic nutcracker syndrome presents large parts.
The diagnosis and the indication of Nutcracker Syndrome for surgical treatment have not been unified during these years.
Recurrent gross hematuria, persittent orthostatic proteinuria were taken into consideration largely in the surgical treatment for Nutcracker Syndrome. Renal vein transposition, autotransplantation and endovascular stents, three conventiaonal options, have been associated with good outcomes and relatively less morbidity, been performed through many countrys.
Extravascular stenting was used on the left renal vein to relieve the outflow obstruction, attenuating symptoms of Nutcracker syndrome, first reported in 1988, has been generalized due to no theraputic coagulation needed postoperatively. To objective application of extravascular stent for nuctcracker syndrome, also to evaluate its safety and feasibility, we reviewed our experience with extrovascular stenting for patients with Nutcracker syndrome.
Diagnostic algorithm for Nutcracker Syndrome was as follows: Patients with symptoms of gross hematuria, flank pain or significent left side varicocele, were performed urine routine test, urinary red cell morpholoogy. Patients with 80% isomorphic red cells were acquired to measure the anteroposterior(AP) diameter and peak velocity(PV) at the hilar portion of the LRV and at the LRV between the aorta and the superior mesenteric artery(SMA) through ultrasonography. Criterion of more than 5.0 for the ratio of AP diameter and the ratio of PV was suspected for the nutcracker syndrome. Computerized angiographic tomography of the abdomen was underwent to delineate the anatomical relation of LRV with aorta and SMA for the suspects.
Through the diagnostic algorithm above, extrovascular stenting for Nutcracker syndrome was done to 16 patients with recurrent gross hematuria, 1 with persittent orthostatic proteinuria from November 2009 to June 2011.
Under general anesthesia, patients were placed in the right lateral decubitus position. Splenocolic ligament was disconnected to expose renal pediclce. Splited the vagina vasorum, ligated left adrenal vein and left gonadal vein routinely, left renal vein was mobilized from renal hilus to inferior vena cave finely. The diameter of LRV at the hilar protion was significent larger than that at the position between the aortha and the SMA. SMA was isolated with peripheral fibrous bundle and raised it, the discontiuation of LRV would be attenuated quickly, which represented the position of Nutcracker syndrome. Thinnd LRV through clamping the hilar portion with rubber belt, if necessary occluded left renal arteries. A reinforced polytetrafluoroethyline graft was applied around the thinnd LRV, unclamp the belt around hilar portion of LRV, which length was fit for the entire LRV to prevent displacement postoperatively.
Symptoms of Nutcracker syndrome, urinal routine test, urinary red cell morphology and ultrasonography of all patients were performed every 6 months after surgery. The follow up period was 6 to 12 months.
5 patients (3 males, 2 females) underwent extravascular stenting through open surgery, the remaining 11 (8 males, 3 females) did through laparoscopic extravascular stenting for nutcarcker syndrome. 7 patients had recurrent gross hematuria, more obvious after exercise. Five had symptoms of left flank pain with associated hematuria, 4 male patients had gross hematuria along with obvious left side varicocele. The duration of symptoms ranged from 3 months to 2 years (mean 17.2 months).
The mean diameters of the hilar and aortomesenteric portions of the LRV were 9.86 mm (range from 5.3 to 14.9 mm) and 2.17 mm (range from 1.0 to 3.0 mm), respectively.
Of the 16 patients, one was found to have chylous ascites, a rare early postoperative complication. Re-exploration was performed to ligate the lymphatic chammels. The remaining 15 patients significently attenuated symptoms of hematuia, gross hematuria resolved in all patients, though 4 having microscopic haematuria. Ultrasonography showed anteroposterior diameter of LRV at the hilar portion and between the aorta and the superior mesenteric artery were improved to 4.7- 6.5 mm( mean 5.4 mm) and 7.0-9.3 mm (mean 8.6 mm), respectively, confirming no recompression of LRV between the abdominal aorta and SMA. Simultaneously, 4 patients along with preoperative left side varicocele were all seen to improve significantly. There was no thrombosis happened despite no therapeutic anticoagulation recommended during 2 years follow up.
Diagnosis of the nutcracker syndrome largely depends on the symptom of haematuria, basic laboratory test results for excluding other causes of haematuria, ultrasonography and computerized angiographic tomography for view compression of LRV at the position between the aortha and the SMA. Considering the process needn't to transplant LRV or to insert entovascular stent, extravascular stenting is a feasible, safe option for the nutcracker syndrome. Patients of nutcracker syndrome having the only symptom of significant varicocele are recommended for surgery from our experience.
