CASE REPORT

Robot-assisted laparoscopic extravascular stent for nutcrackersyndrome

Igor Sorokin1 • Jessica Nelson1 • John E. Rectenwald2 • Jeffrey A. Cadeddu1

Received: 27 June 2017 / Accepted: 27 August 2017

� Springer-Verlag London Ltd. 2017

Abstract Minimally invasive treatment options are a safe

and feasible alternative for treatment of nutcracker syn-

drome. Endovascular stenting has shown promising long-

term resolution of symptoms but can be complicated by

stent migration or thrombosis. Laparoscopic extravascular

stent placement has shown promising results with the

potential to avoid these complications. We report the first

case of extravascular stent placement using the robotic

approach for the treatment of nutcracker syndrome.

Keywords Nutcracker syndrome � Extravascular stent �Robot � Laparoscopy

Introduction

Nutcracker syndrome (NCS) is a rare syndrome caused by

extrinsic compression of the left renal vein (LRV) between

the aorta and superior mesenteric artery (SMA) [1]. Clin-

ical manifestations usually found in patients with a low

body mass index include left flank pain, hematuria,

anorexia, pelvis congestion in females, and left-sided

varicocele in males. Radiographic confirmation of NCS

includes Doppler ultrasonography demonstrating high peak

systolic velocity (PSV) in the LRV and/or a venogram of

the LRV showing narrowing and reflux into collateral

vessels. Patients who initially fail conservative

management are usually offered definitive treatments

which can range from highly aggressive procedures such as

LRV [2] or SMA [3] transposition to less aggressive

endovascular [4] or extravascular [5] stenting of the LRV.

Recently, Wang et al. [6] reported their laparoscopic

experience with extravascular stenting in 13 cases showing

excellent results. We herein report the first case of robotic-

assisted laparoscopic extravascular stent placement as a

minimally invasive option for the treatment of NCS.

Case report

43-year-old female with left flank and pelvic pain for

several years. The pain was quite debilitating and associ-

ated with insomnia, weight loss, nausea, vomiting, and rare

hematuria. A computed tomography scan was performed to

evaluate her flank pain which revealed an incidental 2 cm

left renal angiomyolipoma as well as findings suggestive of

NCS. She then underwent Doppler ultrasonography of the

kidneys which was indeterminate for NCS revealing a PSV

of 85 cm/s at the narrowest portion of the LRV (abnormal if

[100 cm/s). Therefore, she underwent a venogram (Fig. 1)

which revealed severe compressive narrowing of LRV at

the level of the SMA and aorta with reflux into the left

gonadal vein, paravertebral venous plexus, and hemiazy-

gous venous system. These findings were radiographically

consistent with NCS. Because of intolerable pain, she

wished to proceed with an external LRV stent placement to

elevate the SMA off, thus relieving compression.

Thepatientwas positioned in amodifiedflankpositionwith

left side up. After induction of general anesthesia, a Veress

needle was inserted at the umbilicus to create a pneumoperi-

toneum. Then, a 12 mm camera port was placed at the supe-

riormarginof the umbilicus.An8 mmrobotic portwas placed

& Jeffrey A. Cadeddu

Jeffrey.Cadeddu@utsouthwestern.edu

1 Department of Urology, UT Southwestern Medical Center,

5323 Harry Hines Boulevard, Dallas, TX 75390, USA

2 Department of Surgery, UT Southwestern Medical Center,

Dallas, TX, USA

123

J Robotic Surg

DOI 10.1007/s11701-017-0744-7

in the midline below the xiphoid, and another 8 mm robotic

port was placed in left lower quadrant. A 12 mm suprapubic

port was placed for the assistant. The robotic system was

docked and the procedure was commenced by reflecting the

colon, spleen and pancreas medially. The LRVwas identified

as well as the gonadal vein inserting on it which was quite

dilated. The SMA was carefully mobilized off of the LRV.

The anterior aorta adventitial tissue and lymph nodeswere left

in place; however, the bowel was mobilized enough medially

to expose the anterior surface of the inferior vena cava (IVC).

The LRV was dissected out medially to the confluence of the

IVC at the superior and inferior margins. The LRV was then

mobilized off the anterior surface of the aorta and a vessel loop

was placed around it to assist with retraction for stent

placement.

The diameter of the graft to be used for external stenting

was selected using the equivalent diameter formula that

allows conversion of oval geometry to equivalent circular

diameter. And therefore, we used a 10 mm expanded poly-

tetrafluoroethylene (ePTFE) externally supported (ringed)

vascular graft. We measured the length of the LRV from the

adrenal vein to the IVC which was 2 cm long. The graft was

split longitudinally at the back table and two 4-0 Vicryl� stay

sutures were placed at the corners of graft. Using the robotic

needle drivers in each arm, the stay sutures were grasped

underneath the LRVwhile lifting up on the vessel loop to help

pass the graft under the LRV. The graft was positioned

between the adrenal/gonadal insertions and the IVC. The

edges of the split graft were re-approximated with interrupted

4-0 Vicryl� suture and then in two locations, the graft was

secured to the adventitia of the aorta using 4-0Vicryl� sutures

(Fig. 2). With the graft stabilized, the robot was undocked,

and the bed was rotated such that the patient was lying in a

more horizontal position. Using a laparoscopic camera, the

colon and mesentery were seen rotated back into normal

anatomical position. Elevation of the omentum and the

transverse colon, revealed the graft was in good position,

externally stenting the LRV to prevent compression by the

SMA.

The estimated blood loss was minimal and total proce-

dure time was 118 min. Post-operative course was

uncomplicated and patient noted that her pain was relieved

on day 1. On her 6-month follow-up, she still reported

complete resolution of pain verified by CT scan at this time

revealing shielding of the LRV from SMA compression

(Fig. 3). Additionally, relieving the LRV compression

resolved her symptoms of pelvic congestion and no further

procedures on the gonadal vein were required.

Fig. 1 a Left renal venogram during Valsalva showed severe

compressive narrowing of left renal vein at the level of the SMA

and aorta with reflux into the left gonadal vein and paravertebral

venous plexus and hemiazygous venous system. b Left gonadal

venogram done in valsalva showed presence of extensive reflux into

the gonadal and pelvic venous system with pelvic varices and cross-

pelvic collaterals. These findings are consistent with nutcracker

syndrome

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123

Discussion

The treatment of nutcracker syndrome is considered con-

troversial. Conservative management is initially recom-

mended, especially for patients younger than 18 years.

With physical development, juveniles may develop an

increase in fat tissue at the origin of the SMA that may

relieve the LRV entrapment [1]. Adults require surgical

intervention when symptoms are severe or persist after

6 months of conservative therapy [1].

The standard of care for definitive treatment of NCS has

been LRV transposition [7]. This can be approached either

Fig. 2 a Dissection of the renal vein medially to its origin off the

inferior vena cava and laterally to the gonadal vein. b A space was

created between the renal vein and aorta and a vessel loop was placed

around the renal vein to help with stent placement. c The PTFE stent

was split open on the back table and two stay sutures were placed on

the stent to help pull it under the renal vein. d Interrupted 4-0 Vicryl�

sutures were used to close the stent and two additional 4-0 Vicryl�

sutures were placed through the adventitia of the aorta and through

the stent to prevent migration. RV renal vein, IVC inferior vena cava,

SMA superior mesenteric artery, GV gonadal vein

Fig. 3 a Sagittal cut of pre-op CT scan showing SMA compression of LRV. b 6-month post-operative scan showing anterior displacement of a

few millimeters of the SMA from dissection and shielding of the LRV with stent. LRV left renal vein, SMA superior mesenteric artery

J Robotic Surg

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open or laparoscopically [8]. This procedure is labor

intensive and can be complicated by LRV thrombosis and

intractable hematuria requiring nephrectomy [2]. Further-

more, re-intervention rates (mostly for LRV stenosis) have

been noted to be 68% after 2 years [9]. SMA transposition

is another aggressive option for treatment of NCS. How-

ever, it is seldom performed as it has the potential for SMA

thrombosis and intestinal ischemia [3]. Endovascular

stenting is an attractive and simple minimally invasive

option with good results. Chen et al. [4] reported their large

series of endovascular stenting with minimal complications

and resolution of symptoms in 59 of 61 patients. However,

these stents are prone to migration and the potential for

occlusion from thrombosis [10]. One larger series of

endovascular stenting in 75 patients reported a stent

migration rate of 6.7% that can occur months after place-

ment [11]. Furthermore, antiplatelet therapy is recom-

mended after endovascular stenting for at least 3 months

while the stent becomes endothelialized [1].

The first case of extravascular stenting was performed

via an open approach in 1988 to provide a more simple and

physiologic approach to the problem [12]. The first repor-

ted laparoscopic case was performed in the United States in

2001 and was recommended to be the preferred technique

for NCS in light of the potential complications with

endovascular stenting [10]. Since then, only a few sporadic

cases of laparoscopic extravascular stenting have been

reported until recently when the largest series of 13 cases

was published [6]. The authors reported excellent results

with symptom resolution in ten patients, improvement in

two patients, and stent migration in one patient. The stent

migration occurred early in their experience and was per-

haps from an unstable suture.

Careful patient selection is paramount to the success of this

procedure. In addition, the important steps of this procedure

include dissection of theLRV from the origin of the IVC to the

gonadal, placement of stay sutures on the graft to ease

placement around the LRV, and suturing the graft to the

adventitia of the aorta to prevent migration. However, we and

others believe one of the keys to this procedure is release of the

preaortic fibrous tissue at the origin of the SMA to completely

mobilize theLRV away [1, 3, 6]. Perhaps, it is this critical step

that results in the relief of pain associated with NCS but,

reoperation if the pain persists, would be very difficult and,

therefore, placement of an extravascular stent in tandem is

recommended. The shielding from compression that the

extravascular stent provides is certainly helpful. It is also

extremely important to place the stent as close to the origin of

the IVCas this could be apotentialmissed site of compression.

The robot offers an ideal minimally invasive approach

for external stenting to treat nutcracker syndrome.

Laparoscopic surgery is technically difficult and suturing

around vital structures such as the LRV and aorta is safer

with the range of motion the robot offers. Additionally,

large venous collaterals are present in these patients as they

help relieve pressure in the LRV. The improved visual-

ization of the robot can help avoid these vessels and sig-

nificantly lessen operative blood loss.

Conclusion

Extravascular stenting of the left renal vein appears to be a

safe and effective alternative treatment for nutcracker

syndrome. It avoids the potential high risk complications of

venous reconstruction or migration/thrombosis related to

endovascular stenting. The robotic approach offers several

advantages over laparoscopy with improved visualization

and precise suturing around critical sutures.

Compliance with ethical standards

Conflict of interest Igor Sorokin, Jessica Nelson, John E. Recten-

wald, and Jeffrey A. Cadeddu declare that they have no conflict of

interest.

Ethical approval This article does not contain any studies with

human participants or animals performed by any of the authors.

Informed consent Written informed consent was obtained from the

patient for publication of this Case Report and the video. A copy of

the written consent is available for review by the Editor-in-Chief of

this journal.

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