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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_3748_Библиотеки_им_академика_М_И_Перельмана
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50
S. S. Hans
reconstruction are similar to transperitoneal repair. After completion of the proximal and distal anastomosis, the aneurysm sac is closed around the prosthetic graft.
For wound closure, jackknife position is discontinued, and the table made supine.
Partial division of the necessary if required is oversewn over a temporary 16F catheter and pleural air is removed following lung ination. Muscles of the abdominal
wall are closed in layers with number zero or one PDS suture.
Repair ofAAA withCoexisting Horseshoe andPelvic Kidney
Open repair of AAA with coexistent horseshoe and pelvic kidney should be undertaken after complete evaluation of renal arterial supply. In patients with horseshoe
kidney, thickness of the isthmus should be evaluated. Thin-section CTA of the abdomen and pelvis is mandatory in preoperative planning. Renal arteries measuring
greater than 2mm in diameter supplying the horseshoe kidney should be preserved
and reimplanted into the prosthetic graft as Carrel patch (similar to IMA reimplant).
Both transperitoneal and retroperitoneal approaches have been used for open repair
of AAA with horseshoe kidney. If the transperitoneal approach is selected, the wide
isthmus of the horseshoe kidney if present should be persevered with the main body
of prosthetic graft brought behind the isthmus. During retroperitoneal approach,
isthmus and the fused kidney mass are mobilized anteriorly, and the graft remains
behind the horseshoe kidney. For patients with associated pelvic kidney, transperitoneal approach with preservation and reimplantation of renal blood supply, should
be performed.
Take-Home Points
1. The dissection of the aortic neck and bilateral common iliac arteries should be
performed anteriorly and on each side, and passage of vessel loop should be
avoided in order to prevent injury to the posterior lumbar vein (joining the left
renal vein) and injury to the common iliac veins.
2. In patients undergoing left retroperitoneal approach for repair of the AAA with
associated retroaortic left renal vein, the kidney should be left in its bed and
should not be mobilized anteriorly. Injury to the left ureter should be avoided by
keeping the dissection close to the aortic neck and anterolateral wall of the aneurysm. If venous injury occurs, proximal control and distal control distal to the
injury site are obtained with a Kittner sponge. Commonly, the vascular clamps,
which are used to control bleeding from arteries, should not be applied to the
veins as the tear in the veins may extend. Following distal and proximal compression, complete mobilization of the overlying CIA or even transection of the
CIA may be necessary to perform lateral venorraphy for repair of the injured
iliac vein using 5-0 cardiovascular polypropylene running suture. Patients undergoing common iliac vein repair should have a follow-up duplex venous imaging
as the incidence of deep venous thrombosis is increased in such circumstances.
Chapter 4
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Paravisceral Abdominal Aortic Aneurysm
Repair
AlexanderD.Shepard
The paravisceral (PV) aorta is dened as the aorta running from the aortic hiatus to
the renal arteries. Abdominal aortic aneurysms (AAAs) involving this segment of
the aorta represent a unique challenge for open repair. The required operative exposure is unfamiliar to many surgeons and is much more extensive than that used for
infrarenal (IR) AAAs. Clamping of the aorta at this level produces obligatory periods of renal/visceral ischemia, and the reconstruction techniques used are much
more involved than the simple end-to-end anastomoses of IR repair. Careful preoperative assessment is mandatory with particular attention to cardiac, pulmonary, and
renal function. Undoubtedly, the most important preoperative test is a thin-cut,
high-quality computed tomographic angiogram (CTA), which allows careful planning for operative approach, aortic clamp sites, and reconstruction techniques.
The indications for repair are the same as for any AAA and are determined primarily by size, conguration, and the presence of symptoms. Given the risk of these
procedures, our size threshold for intervention is usually a bit higher than the 5.5cm
diameter (for males) and 5.0cm (for females) that we use for IR AAA.
Anesthetic Considerations
Intraoperative monitoring with arterial line, central line, and Foley catheter is routine, supplemented by transesophageal echocardiography as needed. For repairs
where a prolonged period (>30 min) of supraceliac (SC) aortic clamping is
A. D. Shepard (*)
Division of Vascular Surgery, Henry Ford Hospital, Detroit, MI, USA
e-mail: ASHEPAR2@hfhs.org
© The Author(s), under exclusive license to Springer Nature
Switzerland AG 2023
S. S. Hans et al. (eds.), Primary and Repeat Arterial Reconstructions,
https://doi.org/10.1007/978-3-031-13897-3_4
51
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A. D. Shepard
anticipated, a lumbar catheter is placed preoperatively to drain cerebrospinal uid
(CSF) to reduce the risk of spinal cord ischemia. An epidural catheter helps with
postoperative pain management.
Operative Approach
Although juxtarenal AAA can be repaired through a midline, inframesocolic
approach, more proximal aneurysms require retroperitoneal (RP) exposure with
rotation of the abdominal viscera medially. This exposure is most easily accomplished through a left ank (thoracoretroperitoneal or thoracoabdominal) approach
utilizing an oblique incision in the tenth or ninth (rarely the eighth) intercostal
spaces depending on the amount of aortic exposure needed and the level of clamping planned. We use the tenth interspace for suprarenal (SR) aneurysms and the
ninth for most PV AAA.The patient is positioned on a vacuum beanbag in a modied left thoracotomy position with the shoulders at 70–80° to the table. Depending
on the level of distal exposure required, we leave the patient in an almost pure lateral
position (when sewing a tube graft to the bifurcation) or rotate the hips posteriorly
(when iliac/femoral anastomoses are anticipated).
The incision is begun at the umbilicus at the lateral margin of the left rectus
sheath and carried posteriorly into the appropriate intercostal space for 10–15cm.
Taking the incision even further posteriorly (as far as the paraspinous muscles if
necessary) allows more proximal aortic exposure, while extending the incision to
the midline facilitates more distal exposure. The musculature of the abdominal wall
and intercostal space is divided with no effort to avoid entry into the left chest. The
retroperitoneal (RP) space is entered at the tip of the tenth rib. A pure RP approach
can be utilized (our preference) by dissecting the peritoneum away from the transversalis fascia anteriorly, as far as the rectus sheath, and from the lumbodorsal fascia
(the posterior extension of the transversalis fascia) posterolaterally. If one chooses
to use a transperitoneal approach, then it will be necessary to divide the peritoneal
reection of the descending colon laterally after entering the peritoneal cavity. This
peritoneal incision is carried superiorly along the spleen before curving medially to
the aortic hiatus. Great care must be taken to avoid splenic injury with this maneuver.
Division of the diaphragm is performed circumferentially 2–3cm from its lateral
attachments to avoid injury to phrenic nerve branches with the attendant risk for
postoperative respiratory morbidity [1]. This division begins at the costal margin
and is carried posteriorly as far as necessary to avoid tearing the diaphragm during
subsequent rib retraction. A mechanical retraction system (e.g., Thompson or OmniTract) provides excellent exposure. In most situations, an exposure plane posterior
to the left kidney is created. After blunt dissection through loose areolar tissue, the
left kidney and peritoneal sac with its contents are retracted to the patient’s right.
One needs to avoid a deeper plane that can result in stripping the lumbodorsal fascia
off the ank musculature.
4 Paravisceral Abdominal Aortic Aneurysm Repair
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At this juncture, the aorta and aneurysm should be palpable in the base of the
wound. Initial dissection is focused on identication of the left renal artery (RA);
this is the only important structure that can be injured during the initial dissection of
the aorta and serves as a good landmark for identication of other vessels. In thin
patients, this artery is usually visible originating from the left lateral wall of the
aorta/aneurysm, coursing anteriorly to the retracted left kidney; in more obese
patients, some dissection is necessary to nd it. This artery is mobilized back to its
origin off the aorta. In most patients, a lumbar branch of the left renal vein (RV) is
reliably present, crossing over the aorta just below the left RA.Inadvertent transection of this vein can lead to troublesome bleeding, and it should always be sought
and ligated and divided when found. If this venous branch is much larger than normal, concern for a retro-aortic left renal vein (RV) (2% incidence) should prompt
review of the preop CTA.In this setting, exposure of the aorta anterior to the kidney
is necessary to avoid interrupting the venous drainage of the left kidney.
The left posterolateral wall of the aorta/aneurysm is exposed by dividing overlying periaortic fat and lymphatics using an ultrasonic scalpel. This dissection is carried both cephalad and caudal. Immediately above the origin of the left RA, the left
diaphragmatic crus is identied as a rm tendinous band crossing the aorta. Crural
bers are divided several cm along the axis of the aorta and the underlying aortic
wall exposed. In most situations, normal-caliber SC aorta is encountered at this
level; fascia investing the aorta is incised allowing index nger passage anterior and
posterior to the aorta to establish a plane for cross-clamp placement. Lumbar arteries at this level should be avoided. Circumferential dissection of the SC aorta is
unnecessary if the clamp arms pass beyond its far wall. Caval injury is not a concern
at this level.
Suprarenal control is only slightly harder to obtain because of more lymphatic
structures and the proximity of the RAs to the superior mesenteric artery (SMA).
When the SMA originates close to the two RAs (≤ 1.5cm), we avoid SR clamping
because of the risk of damage to the SMA.Supramesenteric clamping is occasionally possible for some SR AAA but is much more involved than SC clamping
because of the presence of more dense lymphatics at this level and the peri-celiac
neural plexus. Dissection of the SMA origin usually requires careful ligation of
these structures to avoid a postop chyle leak. Only the rst 2–3cm of the SMA can
be dissected out from a retro renal approach because more distal exposure is precluded by the crossing left RA.In the unlikely event that more distal SMA exposure
is necessary, the kidney is left in its normal anatomic location and the aorta is
approached anterior to the left kidney as with a retro-aortic left renal vein.
After obtaining proximal aortic control, the origins of the left RA, SMA, and
celiac trunk are exposed as needed. During aortic reconstruction, we favor extraluminal control of the celiac and SMA with small vascular clamps or doubled-up
vessel loops. We nd this less unwieldy than intraluminal control with balloon
occlusion catheters. The distal AAA sac is next exposed by dividing overlying tissues with an ultrasonic scalpel taking care that the left ureter is retracted medially
along with the peritoneal sac. The left iliac is identied distally and
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A. D. Shepard
circumferentially mobilized. The right iliac can be more difcult to control because
of its adherence to the caval conuence. Dissecting this vessel out a few cm distal
to the aortic bifurcation and avoiding circumferential mobilization can minimize the
risk of venous injury. Easily accessible lumbar arteries arising from the aneurysm
sac are ligated to reduce bleeding after opening the sac. Lumbars at the level of the
proximal neck should be preserved if possible (Fig.4.1).
Aortic clamp level: The level of proximal aortic clamping is dependent on the
anatomy of the aneurysm and the presence of aortic plaque burden as dened by the
preoperative CTA.Clamping a diseased aorta can result in renal/visceral and lower
extremity atheroembolism. The more proximally the aorta is clamped, the greater
both the renal/visceral ischemic burden and cardiac strain so the most distal feasible
clamp site is preferred. When SR clamping is not possible, we have preferred SC
over SM clamping because it is less cumbersome, and the SC aorta is reliably the
least diseased segment of the abdominal aorta. SM clamping maintains some visceral perfusion through the celiac and is associated with less cardiac strain; however, the SMA must be controlled to prevent signicant backbleeding. Mannitol
(25 g) is always administered 20 min prior to aortic clamping to enhance renal
protection. A bicarbonate drip (0.05mEq/kg/min) is also started prior to SC clamping to minimize the associated acidosis. With some PV AAA, it is sometimes possible to clamp the IR aorta rst, if the neck is not too aneurysmal or diseased; this
maneuver allows control of backbleeding lumbars in the AAA sac without extending precious visceral/renal ischemia time. When using SC clamping to perform a
juxta−/suprarenal aneurysm repair, backbleeding from uncontrolled visceral and
segmental branches can be controlled by inating a 10cc Foley balloon catheter in
the paravisceral aorta. We routinely heparinize prior to clamping regardless of
clamp level to reduce the risk of both large vessel and microvascular thrombosis, a
cause of multiorgan failure, which can complicate these procedures [2]. Careful
Fig. 4.1 Exposure of a
paravisceral AAA through
a left ank retroperitoneal
approach
4 Paravisceral Abdominal Aortic Aneurysm Repair
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communication with anesthesia is necessary during clamping/unclamping. Blood
should be in the room and an autotransfusion device available when opening the
aneurysm sac.
Vital organ ischemia protection: Proximal aortic clamping is accompanied by
obligatory renal +/− visceral ischemia). Acute kidney injury (AKI) is a common
complication of these repairs. Keeping clamp times to a minimum and optimizing
renal hemodynamics prior to clamping are important. When coming from the left
ank, the right RA is in a dependent position and cannot be clamped prior to aortic
clamping. Mural thrombus or other sac debris can “drop” into this artery when/after
opening the aneurysm sac; for this reason, we often insert a small balloon-tipped
occlusion catheter into the origin of this vessel soon after the aneurysm is opened.
When anticipating >30min of renal ischemia or in patients with chronic kidney
disease, cold renal perfusion is routinely performed to reduce renal metabolic
demands. Balloon-tipped Pruitt perfusion catheters (9Fr for large RAs or 5Fr for
smaller or diseased RAs) are inserted, and 250mL of 1°C Ringer’s lactate solution
(plus heparin, mannitol, and methylprednisolone) is infused into each kidney followed by 50mL q 15min for the duration of clamping. The value of this adjunct in
the prevention of AKI is well described [3]. We have also cold perfused the SMA
(500mL followed by 75mL q 15min) during SC clamping for visceral protection
noting less coagulopathy and hemodynamic changes with unclamping. Although
spinal cord ischemia is rare with PAAA repair, we undertake a spinal cord protection protocol whenever we anticipate an SC clamp time more than 30min. A preop
lumbar drain is placed and 50–75cc of CSF drained following which the drain is set
to maintain an intrathecal pressure≤10cmH2O.We avoid high-dose vasodilators
during cross- clamp and employ moderate passive hypothermia to 34°C.
Aortic reconstruction Techniques: Albumin impregnated Dacron grafts are preferred for these reconstructions to avoid the needle hole bleeding and perigraft seromas associated with PTFE. The overwhelming majority of repairs can be
accomplished with a 20 or 22mm diameter graft. The type of proximal anastomosis
performed is dependent on the proximity of the renal and visceral arteries to each
other and normal aortic caliber. For JR AAA (dened as an aneurysm without an IR
neck suitable for clamping/anastomosis), an end-to-end anastomosis is performed
to the aorta immediately below/adjacent to the RAs frequently taking stitches
through the lower borders of the RA ostia (Fig.4.2). More proximal aneurysms
require some type of beveled anastomosis incorporating the origins of the renal/
visceral arteries. There are several options that depend on the relationship of the
RAs to the aneurysm. The simplest option leaves the RAs on an anterior tongue of
the aorta (along with the SMA and celiac as needed) using a graft with a posterior
bevel (Fig. 4.3). This approach is only possible when most of the aneurysm is
located posteriorly and the two RAs originate close to each other anteriorly. Far
more commonly, the RAs are separated by aneurysmal aorta and it is necessary to
use a lateral bevel. With this reconstruction, the right RA, SMA, and celiac are left
on the aorta medially and the left RA and its origin excised from the aortic wall. The
graft is trimmed with a lateral bevel and sewn in place with 3-0 polypropylene
56
Fig. 4.2 Construction of proximal aortic anastomosis immediately below the RA (and incorporating the RA ostia into the suture line as needed) during JR AAA repair
A. D. Shepard
Fig. 4.3 Proximal aortic reconstruction with a posterior beveled anastomosis, leaving the celiac,
SMA, and both RAs on an anterior segment of the aorta. To utilize this type of reconstruction, both
RAs need to arise anteriorly off the aorta in close proximity to each other
(48cm length) using the inclusion technique (Fig.4.4). This anastomosis is started
at the level of the dependent right RA and runs along the posterior wall taking
double-thickness bites (Creech technique) (Fig.4.5). At the edge of the trimmed
aortic wall, the suture line is transitioned to single-thickness bites. The other end of
4 Paravisceral Abdominal Aortic Aneurysm Repair
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Fig. 4.4 Proximal aortic reconstruction with a laterally beveled anastomosis, incorporating the
celiac, SMA, and right RA on a segment of the aorta and either bypassing or reimplanting the left
RA.This is more commonly utilized than the reconstruction shown in Fig.4.3
Fig. 4.5 Laterally beveled
proximal anastomosis with
perfusion catheters in SMA
and both RAs and
construction of posterior
wall suture line. Small
clamp is on the celiac
artery
57
the suture is carried around the right RA anteriorly until the two stitches meet near
the SMA.When utilizing the inclusion technique, it is important to leave behind as
little aorta as possible to minimize the risk of recurrent aneurysm formation from
degeneration of the remaining aortic wall. Following aortic ushing, the perfusion
catheters are removed, the suture line is secured, and ow is restored rst to the right
RA and then the viscera after careful communication with the anesthesia team.
At this point, one can proceed with revascularization of either the lower extremities or the left RA.We usually go with the distal aorta rst (or at least one iliac) to
both unload the heart and to restore hypogastric ow to improve spinal cord perfusion. Continued cold perfusion of the left RA protects the kidney during distal aortic
reconstruction, or alternatively, a small Pruitt carotid shunt can be used to provide
ow from a sidearm graft off the aorta. The left RA can either be reimplanted
directly on to the prosthetic aortic graft, utilizing a small button of aortic wall, or it
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A. D. Shepard
can be bypassed with a previously constructed sidearm graft. If a sidearm graft is
used (our preference), it is imperative that this conduit (usually slightly oversized at
7 or 8mm in diameter) be appropriately positioned on the aortic graft to avoid subsequent kinking (2 o’clock position with the SMA at 12 o’clock). The graft to RA
anastomosis should always be performed under a fair amount of tension since there
is invariably graft/artery redundancy when the kidney is returned to its normal location, which can lead to kinking.
With aneurysms originating well above the celiac (true extent 4 thoracoabdominal aneurysm), an end-to-end anastomosis between the graft and the descending
thoracic aorta is necessary with reimplantation of the celiac, SMA, and right RA as
a separate inclusion patch (Fig.4.6). When the origins of the visceral and right renal
arteries are widely spaced apart, it may not be possible to use the inclusion technique without leaving an unacceptable amount of aneurysmal aortic wall behind. A
prefabricated graft with four sidearms—celiac, SMA, and both RAs (Vascutek®
Coselli thoracoabdominal graft)—is useful in this situation as it is in patients with
suspected connective tissue abnormalities (Fig.4.7). Great care is needed when
using this graft to ensure that the sidearms line up with their respective branches.
After performing the proximal aortic anastomosis, we move to the right RA anastomosis, which must be done prior to the others or risk losing exposure to this vessel.
Following reperfusion of the right kidney, we connect the perfusion catheters present in the SMA and left RA to their respective limbs and restore ow to these organs.
This approach reduces renal/visceral ischemia and allows an unhurried distal aortic/
iliac anastomosis. After lower-extremity revascularization, the SMA, celiac, and
nally the left RA grafts are performed sequentially. It is important to do the left RA
last to maintain exposure for the visceral anastomoses and reduce the risk of tearing
Fig. 4.6 Extent 4 TAAA repair showing end-to-end proximal aortic anastomosis and Carell patch
reimplantation of the celiac, SMA, and right RA on a small island of the aorta. The left RA is
reconstructed with a short sidearm graft
4 Paravisceral Abdominal Aortic Aneurysm Repair
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Fig. 4.7 Extent 4 TAAA repair with a preconstructed 4-branched (Coselli) graft. Sidearm grafts
are individually sewn to the celiac, SMA, right RA, and left RA.This graft must be carefully measured/trimmed and aligned rotationally prior to proximal anastomotic construction. AAA abdominal aortic aneurysm, JR juxtarenal, SMA superior mesenteric artery, RA renal artery, TAAA
thoracoabdominal aortic aneurysm
59
this bypass during visceral reconstruction. To avoid kinking, the Coselli graft limbs
are left very short (10–15mm).
Following completion of all anastomoses, patency of reconstructed vessels is
checked by Doppler probe auscultation and the hemostatic prole corrected with
protamine/clotting factors as necessary. We have found point-of-care thromboelastography very useful. Closure is performed after placement of #19 Fr postero-basal
channeled pleural tube; 2-0 or 0 Prolene is used on the diaphragm, looped #1 PDS
for rib approximation, and layered 0 or 2-0 PDS for the wound. A spinal cord protection protocol is maintained for 24h in all patients with a lumbar drain.
Conclusions
Aneurysms of the PV aorta can be repaired with morbidity and mortality approaching that of open IR AAA repair in experienced hands [4]. There are several keys to
success: First, careful operative planning based on high-quality preoperative imaging. This is not an operation where one “opens up the hood” and gures out things
on the y. A second key is to reduce blood loss by avoiding venous injuries, ligating/
clamping lumbar arteries prior to opening the sac, and controlling backbleeding
branches. Minimizing vital organ ischemia by keeping clamp times low and utilizing adjuncts to extend ischemic tolerance (cold renal/visceral perfusion, CSF drainage) is also critical. And nally, technical precision as opposed to speed will assure
the best possible outcome.
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