Nutcracker Syndrome: The Renal Vein Transposition


Case Report

Patient is a 43 year old woman who had been having bouts of severe left sided abdominal pain for several years with worsening episodes of nausea and vomiting resulting in several visits to the emergency room. She has also had microscopic hematuria. Gastrointestinal workup including gastric emptying study, esophagogastroduodenoscopy and colonoscopy were negative, as was a workup for kidney stones. Eventually she was referred to my clinic for management of nutcracker syndrome. She denied lower abdominal pain nor excessive menstrual bleeding.

On examination, she was tender over the left kidney and flank. Laboratory examination was positive for microscopic hematuria. CT venography (below) showed an obstruction of her left renal vein by the superior mesenteric artery. Drainage via gonadal vein was not demonstrated, and no pelvic varices or complex of retroperitoneal veins was apparent.


Duplex showed the narrowing in the left renal vein and spectral Doppler showed elevated velocities across the compression caused by the superior mesenteric artery (below). The collecting system was not obstructed.

venous duplex14.jpg


Treatment options included endovascularization with a large stent in the left renal vein, left renal vein transposition to a lower position on the inferior vena cava, left renal autotransplantation, and left nephrectomy. Stent placement comes with a degree of risk for cardiopulmonary embolism which may require a sternotomy to fish out an errant stent. The risk for this in the US is because the largest nitinol stents available are 14mm in diameter which might result in undersizing in a vein that could easily dilate to well over 20mm. Larger nitinol stents for venous applications are available in Europe but currently are not approved in the US (yet). Wall stents, while certainly wide enough, have the problem of being long and stiff when not fully deployed. A 22×35 Wall stent may be 50mm long if deployed inadvertently into a tributary vein or contrained at the narrowing. Because it slides easily, passing balloons in or out can cause it to slip out of position. Because this stent elongates when compressed and packed, deployment is challenging and it is prone to “watermelon seeding,” a set up for embolism. It does have the virtue of easy reconstraining.

My friend and recent host for Midwest Vascular Surgery Society Travelling Fellowship, Dr. John V. White, in Chicago, seems to have solved this problem by a multistep process of predeploying a temporary suprarenal IVC filter, deploying a stent (whatever fits), leaving the filter as a protection against stent migration for 4 weeks until the stent permanently seats itself through scarring/intimal ingrowth, then removing the filter.

I chose to perform venography and renal vein transposition. The patient was placed in a supine position on a hybrid angiographic operating room table and her right femoral vein was accessed. She was placed in 15 degrees reverse Trendelenberg which is about the upper limit possible. Venography below.

Arrow points to left ascending lumbar vein which is taking most of the reflux. It drains the left kidney across the midline via retroartic channels to the IVC
The films showed left renal vein compression by the superior mesenteric artery with outflow via the ascending lumbar vein, both supra and infrarenal tributaries. A midline exposure was performed and the retroperitoneum opened as in an transabdominal aortic exposure. The vena cava was exposed, and the left renal vein was mobilized by ligating and dividing its tributaries. A point 5cm below the tributary point was marked on the IVC, and this was the target for transposition.


After heparinizing and clamping, the renal tributary was taken with a 5mm cuff –this would ensure proper length without narrowing the IVC.


The vein was anastomosed and flow was excellent by pulse Doppler.


She recovered well but had a longer stay because of an ileus, being discharged on day 5. Because she lived at a distance, and came back for followup the following week prior to boarding a plane for home. She no longer had the left sided abdominal pain and there was no hematuria. CT showed excellent drainage through the transposed vein.

pre and post ctv comparison.png

Followup will be periodic (6 monthly) renal venous duplex from home. Given that there was minimal tension on the repair, I expect this to do well.


Nutcracker syndrome is one of the many unfortunate consequences of our bipedal lifestyle. The small intestines hang like baggy sausages off the branched stems of the superior mesenteric artery (SMA), and in some individuals, the SMA compresses the left renal vein against the aorta. The left renal vein receives up to 12-15% of cardiac output via the left kidney, and with outflow obstruction, drains the blood through small collaterals. The renal venous hypertension results in swelling of the left kidney with subsequent left renal colic -with flank and abdominal pain, nausea, and vomiting. There is hematuria which can be gross or microscopic. With drainage via an incompetent gonadal vein, varicoceles can occur with discomfort in men and pelvic varices with pelvic congestion syndrome can occur in women.

Diagnosis is challenging because it is one of the relatively rare non-gastrointestinal causes of abdominal pain (table).

  1. Mesenteric ischemia
  2. Median arcuate ligament syndrome
  3. Nutcracker syndrome
  4. Neuromuscular
  5. Urolithiasis
  6. Inflammatory aortitis/arteritis
  7. Hypersplenism
  8. Portal hypertension
  9. Arterial aneurysm
  10. Infections
  11. Pelvic Congestion Syndrome
  12. Endometriosis
  13. Hernias 

A history of left sided abdominal pain, flank pain, nausea, vomiting, associated pelvic pain, and episodes of hematuria are diagnostic. Examination is typically positive for left renal tenderness and flank tenderness. Laboratory examination include urinalysis for hematuria. Duplex, while technically challenging, will show renal venous compression with velocity elevation or loss of respirophasicity, CTA will typically show obstruction of the left renal vein with filling of collaterals, as will MRV.

Venography should be done in a stepwise manner (White protocol) to fully demonstrate the maldistribution of blood. That is the key word, maldistribution. I learned from my fellowship with Dr. White that performing venography in as upright a position as possible recreated the pathophysiology, the physics, particularly for pelvic congestion and nutcracker. Remember, this is a disease of bipedalism, of upright posture. Many negative studies done supine become positive, as the contrast will fall to where it prefers to go. As I have stated in the past, on the venous side, demonstrating drainage has different imaging needs than demonstrating flow. Pathologic venous drainage has three characteristics:

  1. Varicose veins develop as an end stage process
  2. Reversal of flow or reflux is demonstrated, particularly into small tributary veins
  3. The midline is crossed in these usually small, now larger, collateral veins

While pressure gradients are nice if they are large, they are difficult to assess when they narrow to 1-2mmHg, particularly if they vary with cardiac cycle and respiration. Because we are assessing drainage, the distribution of contrast and the direction it goes is particularly important, and far more sensitive than pressure measurements.

Venography was done per a modification of Dr. White’s protocol for pelvic congestion:

  1. Steep reverse Trendelenberg
  2. Hand injection 10mL half diluted contrast, gently as to not create false reflux
  3. Runs with catheter in left EIV, right EIV, left renal vein, right renal vein
    1. With pelvic congestion workup, add selective bilateral gonadal and internal iliac veins.


I have started transposing gonadal veins when they have enlarged from chronic reflux (link, ref 2). Renal vein transposition was chosen because her ovarian vein was competent and too small to transpose (ref 1-3). While the patency rate of stents in veins seems to be acceptable, long term data is unavailable. Also, venographic appearances are deceiving -see the in-vivo measurement of the left renal vein after dissection:

Left renal vein at widest is 22mm, with expansion, possibly up to 28mm, but is relatively short. Do you see the SMA?
The variability in diameter and length of the Wallstent in the 22-24mm diameter range makes this a challenging deployment. Given that I would not be able to closely follow this young patient, I felt compelled to recommend a durable solution (ref 4).


  1. White, J. et al, Left ovarian to left external iliac vein transposition for the treatment of nutcracker syndrome. J Vasc Surg Venous Lymphat Disord. 2016;4:114–118.
  2. Miler R, Shang E, Park W. Gonadal Vein Transposition for the Treatment of Nutcracker Syndrome. Annals of Vascular Surgery 2017, July 6. in press.
  3. Markovic JShortell C. Right gonadal vein transposition for the treatment of anterior nutcracker syndrome in a patient with left-sided inferior vena cava. J Vasc Surg Venous Lymphat Disord.2016 Jul;4(3):340-2. doi: 10.1016/j.jvsv.2015.09.002.
  4. Erben Y, Gloviczki P, Kalra M, Bjarnason H, Reed NR, Duncan AA, Oderich GS, Bower TC. Treatment of nutcracker syndrome with open and endovascular interventions. J Vasc Surg Venous Lymphat Disord. 2015 Oct;3(4):389-96. doi: 10.1016/j.jvsv.2015.04.003.

Case report up on Annals of Vascular Surgery -Gonadal Vein Transposition for Nutcracker Syndrome


A case report co-authored by my recently graduated trainees, Drs. Roy Miler and Eric Shang. An update to be presented at Midwest Vascular Surgery Society Meeting in Chicago.

Nutcracker Syndrome: A Simplified Approach With Gonadal Vein Transposition


The patient is a young woman in her twenties who developed severe right sided abdominal and back pain about 4 months prior to presentation associated with bouts of bloody urine. Activity and standing exacerbated her pain and inactivity and recumbency relieved it. She gained 15 pounds because of her inactivity. Examination was significant for tenderness over her left kidney. Urinanalysis showed positive proteinuria and hemaglobinuria.

Prior to consultation with me she had had an MR venogram showing compression of her left renal vein by the superior mesenteric artery (nutcracker phenomena). The presence of hematuria, proteinuria, and pain (albeit atypically right sided) made it nutcracker syndrome.

MRV color_Image006
Dilated left gonadal vein and pelvic varices indicate left renal vein (LRV) ouflow obstruction by the superior mesenteric artery (SMA)

I ordered a renal duplex and a CT venogram for procedural planning.


On the duplex, the proximal left renal vein (LRV) was not visualized. The right kidney had normal parenchymal appearance and blood flows, while the left, the kidney appeared distended and had flows consistent with outflow obstruction.

spectral kidneys
Spectral Doppler flows show respirophasicity in right renal vein(RRV), outflow obstruction on left renal vein (LRV)
Duplex kidneys bmode
The left kidney is swollen and tender.

CT Venography showed the gonadal vein to be an important outflow vessel to the left renal vein with dilated proximal segment and reflux into pelvic varices.


CTA processed_5CTA processed_4

A left gonadal vein to iliac vein transposition was planned via a left lower quadrant retroperitoneal exposure. On the table, a venogram was performed with selective access of the left renal vein.


The injection from the LRV showed severe compression of the LRV with a channel only slightly larger than the sheath and avid reflux into the gonadal vein. Selective access into the gonadal vein and venography from a confluence in the pelvis showed that flow was one way from the LRV into the gonadal vein and this filled a large region of pelvic varices.



The gonadal vein was large caliber and refluxed into two large veins in the pelvis. The one that fed the varices was not selected for transposition, but rather the longer straighter tributary. A catheter was left for easier identification during the dissection.

A left lower quadrant incision was made and a retroperitoneal dissection performed exposing the gonadal vein and iliac vein.




Prior to ligation of the tributaries, a sheath was inserted and through this a LeMaitre valvulotome was brought up to the left renal vein and carefully deployed and pulled back, cutting the valves. This greatly increased the outflow from the vein as evidenced by the height of the blood spout from the vein when the sheath was removed. The varices were ligated at their root -treating them definitively. Transposition was to the external iliac vein, and I could see the feasibility of a laparoscopic or robotic approach to this operation (ref 3).

Completion venography showed excellent flow from the LRV down the gonadal vein into the iliac venous system.


The patient lost less than 10mL of blood and was discharged on postop day 2. Gratifyingly, all of her preoperative pain resolved and her UA showed no more hemoglobinuria or proteinuria.


The described treatment options for nutcracker syndrome include (ref 1):

  1. Medical therapy aimed at decreasing renal venous hypertension (for hematuria)
  2. Renal autotransplantation
  3. Left renal vein transposition
  4. Left renal vein to vena cava bypass (autologous or PTFE)
  5. SMA transposition
  6. Nephrectomy
  7. Gonadal vein to IVC bypass
  8. Exovascular stenting (wrap of renal vein with ringed PTFE graft)
  9. Endovascular stenting

Many of the operations are of historic interest. Stenting deserves some comment. The patient self referred because she had read multiple reports of cardioembolization on internet support group comments. The largest nitinol stent (self expanding) available is 14mm. Wall stents in larger diameters are available, but are stiff, poorly conformable, and will elongate if constrained by a non-dilating stenosis like the external compression by the SMA. While acceptable results have been reported, the long term results (20-70 years) for younger patients is unknown. Migration is highly morbid, and usually to the heart, requiring sternotomy and cardiotomy to retrieve the stent. Optimally, a conforming 16-28mm self expanding stent should eventually become available, but conformability is typically inversely proportional to radial strength, and it is the less conformable stents that migrate. Work is ongoing to bring larger diameter nitinol stents for venous indications. The difference between May-Thurner Syndrome and Nutcracker syndrome isn’t merely the size of the veins and stents. The iliocaval confluence is relatively static with some movement of the lumbosacral joints and well suited for treatment with the relatively nonconforming Wall Stents. The left renal vein under the SMA is a very dynamic environment with motion of the SMA and the kidneys with respiration, ambulation, and activity leaving stents vulnerable early to migration and later to fracture.

The left renal vein transposition to the IVC is a nice operation with a good track record (ref 2). The downside is the long midline incision required with transperitoneal exposure. There is bleeding risk and postoperative complications of ileus, wound infection, and small bowel obstruction. Looking at the CTV, it seems obvious that the gonadal vein crosses over the iliac vein in the pelvis and would be a straightforward, less morbid, less invasive option. A review of the literature reveals only a single reference discussing three cases of left renal vein transposition (ref 3), and it was done with a surgical robot. I think that a laparoscopic approach would be simpler and less invasive and will consider developing this if volumes justify it. That said, the open retroperitoneal approach is very straightforward and well used exposure. Using venography to set up and then confirm the results of the transposition was helpful. I don’t think that measuring pressures and diameters and taking calipers to calculate stenoses is all that useful and in some instances a harmful method of justifying endovascular treatment of nutcracker phenomena in the absence of serious symptoms and a careful deliberate workup which includes a good history and physical, a UA, a duplex and CTV.

Intervening on the gonadal vein to iliac vein anastomosis should be straightforward from a groin or thigh venous access on the ipsilateral side. This operation doesn’t preclude any future interventions on the LRV. The pelvic varices were treated with direct ligation. The patient’s pain was successfully relieved in the short term.

Conclusion: Open retroperitoneal left gonadal vein to iliac vein transposition with gonadal vein valvulotomy is effecting in treating nutcracker syndrome.


  1. Kurklinsky AK, Rooke TW. Mayo Clin Proc. 2010 Jun; 85(6): 552–559.
  2. Reed NR et al. J Vasc Surg. 2009 Feb;49(2):386-93;
  3. White JV et al. J Vasc Surg Venous Lymphat Disord. 2016 Jan;4(1):114-8.