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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
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
J Robotic Surg
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
123
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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